2024 day1

2023/go/.vscode/launch.json

@@ -0,0 +1,16 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Package",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "args": ["16"],
+            "program": "${fileDirname}"
+        }
+    ]
+}

2023/go/day14/day14.go

@@ -0,0 +1,95 @@
+package day14
+
+import (
+	_ "adventofcode2023/utils"
+	"adventofcode2023/utils/grid2d"
+	"adventofcode2023/utils/inputs"
+	"fmt"
+	_ "strings"
+)
+
+func Part1(input string) int {
+	grid := inputs.ToGrid2D[rune](input, "\n", "", ' ', func(c string) rune { return rune(c[0])})
+//	fmt.Println(grid.StringWithFormatter(func(c rune, x int, y int) string { return string(c)}))
+	slide(grid)
+//	fmt.Println(grid.StringWithFormatter(func(c rune, x int, y int) string { return string(c)}))
+	return score(grid)
+}
+
+func Part2(input string) int {
+	grid := inputs.ToGrid2D[rune](input, "\n", "", ' ', func(c string) rune { return rune(c[0])})
+//	fmt.Println(grid.StringWithFormatter(func(c rune, x int, y int) string { return string(c)}))
+	x:= 0
+	for j:=0;j<125;j++ {
+		for i:=0;i<4;i++ {
+			slide(grid)
+			grid = rotate(grid)
+		}
+		if  score(grid) == 101375 { 
+			fmt.Println(j, j - x)
+			x = j
+		 }
+	}
+	fmt.Println(score(grid))
+	for j:=999999840+125;j<1000000000;j++ {
+		for i:=0;i<4;i++ {
+			slide(grid)
+			grid = rotate(grid)
+		}
+		if  score(grid) == 101375 { 
+			fmt.Println(j, j - x)
+			x = j
+		 }
+	}
+//	fmt.Println(grid.StringWithFormatter(func(c rune, x int, y int) string { return string(c)}))
+	return score(grid)
+}
+
+
+func slide(grid *grid2d.Grid[rune]) {
+	G := grid.Matrix()
+	R := len(G)
+	C := len(G[0])
+	for c:=0;c<C;c++ {
+		for r:=0;r<R;r++ {
+			for dr:=0;dr<R;dr++ {
+				if G[dr][c]=='O' && dr>0 && G[dr-1][c]=='.' {
+					G[dr][c]='.'
+					G[dr-1][c] = 'O'
+				}
+			}
+		}
+	}
+
+}
+
+func rotate(grid *grid2d.Grid[rune]) *grid2d.Grid[rune] {
+	G := grid.Matrix()
+	R := len(G)
+	C := len(G[0])
+	New := grid2d.NewGrid[rune](R, C, '?')
+	NG := New.Matrix()
+	for r:=0;r<R;r++ {
+    	for c:=0;c<C;c++ {
+      		NG[c][R-1-r] = G[r][c]
+		}
+	}
+  	return New
+}
+
+func score(grid *grid2d.Grid[rune]) int {
+	ans := 0
+
+	G := grid.Matrix()
+	R := len(G)
+	C := len(G[0])
+
+  	for r:=0;r<R;r++ {
+    	for c:=0;c<C;c++ {
+    		if G[r][c]=='O' {
+        		ans += len(G)-r
+	  		}
+		}
+	}
+  	return ans
+}

2023/go/day14/day14_test.go

@@ -0,0 +1,37 @@
+package day14
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(
+`O....#....
+O.OO#....#
+.....##...
+OO.#O....O
+.O.....O#.
+O.#..O.#.#
+..O..#O..O
+.......O..
+#....###..
+#OO..#....`)
+	require.Equal(t, 136, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(
+`O....#....
+O.OO#....#
+.....##...
+OO.#O....O
+.O.....O#.
+O.#..O.#.#
+..O..#O..O
+.......O..
+#....###..
+#OO..#....`)
+	require.Equal(t, 64, r)
+}

2023/go/day14/input.txt

@@ -0,0 +1,100 @@
+O...#.O......#...##....O#.#.OO...O.#OO#.....#O.O.....#......#.OO...O...O..O#O#....#...O..O...O.....O
+.OO......O.OO.O.#.#O.O...#.##OO.....#.#O#...OOOOO..##O#O..O#O.##O...#O....O#.#.OO....#.........O.O.O
+......O.O.O.....O.#.#.#OO#O#.O...O.#.......#O....#.O.#....OOO...#....O#O.......#......O...O##...O...
+O...##O..#....OO.OO....O...O...O#..##.OOO..O..#OO....###....OO.O.O...........O...O..O.....#.#..O.O#.
+............#.#.##O.O.#.#OO#........O..O.O..##....O.#..#O..O...O#.#.#.........O...........OO......O.
+#.OO........#..#O.#......#....#....#......OO..OO...O#...#...#..##..O#.O......#.#..O..#O#...#..#.O#.O
+O.O.##...........O...O..O...O.OO.......##....#...O.....##...#.....OO...O.O#...OO..........O...O..#O.
+.O##....#.O#O....O.O.#.#O.O#..OO..##..#OO.#...#......#.#O#.....O...O#.O...#..O.#.#......#.##.O....O.
+.........#..#.O..O..O.O...#.#.O...#.OOO.##..#.O.....OO#....O...OOO#.O#....##O..#.O.O.....O.O.O.O..O.
+......#O.....OOO###.O..O####O.#.O...............#..O......##O...#.#..###...O....#O...OO.OO.O......O.
+#.O....#.O..#O...#...#...O....OOO.#O.#.#..#.....#.#..OO..#OO.......#OO.OOO....O.#O.#.O......####..O.
+OOOO...#.OO.#....O...O.O...##....#OO...O.##.O.....###..O........OO..O.O.......#.#...O..#..O.#..O....
+OOO..##....O...O.....O#..O.O.#..O..#.#.#..O........O..#OOO.....#....O#OO.#.#.....O..#..O...O..O.#OO#
+...##.#.##.#O....O#..O..O.........#.#.#O...O.......O...O#..OOOO....O...O.OO#.O.##...#....O..O.......
+....##.###OOO.O...#.......OO....OOO....O.OO#..O.#..OO....OO......O..OO...OOO.OO#...#..OOO..O.###O...
+O###O.....O.O.#O#.O.O#O.O###.....O..O........#....#..O#..#.#..O...........#......#OO........O..O####
+.#.#.OOO.O.......#O..O.#..O.OO.OO.O..O.#.#...O.O.OO..##..O...#...#O#..O.........O.O..O.O#....O..#O..
+.#..#O.#O..#.O.O.O...#OO....#...O....O..O.O...#..#.##O.O..O..#O.....OO##...O#.......O#O.#..........#
+#O...#.#OO.O...#O...O...#.#.O#..#.O#.###.#......O..O....#..#.OO..#....O..O.O....#.O.O.O.#..O..OOO..O
+O.....#...#.#OOO.OOOO..#O.O.#...O.##..OO..#O...#.....OO#..#.#...O##OO...O.....O..#...#...........O.O
+.##.O#.O..#O#.O##.O.#.........##.O......#OO...OO.......#...#O.O#...O..#.#...O..#...#O...O.#....OO.OO
+.O#OO.O..#...#..O..O...##.O....###O.....O...#.#OOO...OO...O.......#.#.#.OO....#OO.#..O..........OO..
+.....#OO.O..O.O.O...O.O#.#.O...O..#...O##.......#......#O...#.#.#....#..O.O..#..........O..#.#..#O..
+...O.O.O.OO...O#..O..OO..O#.#.O.#OO..O.O..OO..O#...#.O#...O.......#..#..O..##..O..#O......O.OO...O.O
+#.O....O.O.#...O.....O.....O#......#.#..OO...#.....O.#.#.O...#.#....#....O#.O.#......#OOO.O...O#....
+...OOO......#..O..O#.......#....O#OO..#O.#.#...#...O.O..OO..#.O...O..#.....OO..O..#...#.O...O#..O.OO
+#OO.OO#.OOO...##............O....O.O..#.##.#.O.........##...#O.O..#................#..O.O.O#O.O#..##
+.O.O.O##..#O.O#O...##.#OO#...#.OO#..O...O#...O....O#..OO....O....#...O...#OO.OO#O....#..O..#OO....O.
+.OO.#.......#...O...OO..#..OO.O.O.OO#O.O.O...O....O#..#.O.........O..#.O...#.#...O.O......O........O
+.O....##..#....#.....O.#...O.O.#....#....OOOO...O.O###.O........O.....O.O..#.##OOO.O.......#.#.O..O.
+.#.....O...#.O...#........#...#....#OO.O...O#O........OOO...#.O....OOO#.O.....OO....#.#...#..OO..#..
+OO.OO...O..#..#O....O.O....OOOOO.#O.#O.O...#.O....O#.O.O.#O.#...#..O...O.#O.O.#..O....OOO......#.O#.
+.O##..OO.....#.OO..#..O..#...#.#........O..OO...#O..O....#..O..O#.....O#..##O..O#.##.#...#.O..O.O.O.
+..#...#O.....OO#.....O..#.#O.#.#..#..O.....#...OO.#.....O..O.O##.O.....OOOO.#O.....O.#..O........#.#
+.#.#O..O.O..#..O##.....O.OO...##.........O...####..O..O....#O..O.....##........O.#..#.#OO.#..O.##.O#
+#...#.O....OO......#O...#O..O#..#O#O.#..#.....OO....OO#..#O....O.O..#.O.#.....O#.O.OO..O#.O.O..O.O#.
+OO....OO......#O........#O...#.#..O##....O#..#.#O.O.#....O..O..O.O....O.......#..OOO#.........O....O
+O.....#O.OO##......#O##..O..O...##..O..........O..OO.O..#O....O..OOO#OO.##..#....O#..#...O.O.O...O..
+.............#.#.#.O...#.#..#......O.#.O..#....#..##....#.##.##.#.O...O.O..#.#.#...OO....O..#O..#..O
+.O.#.....O.O..O..##O...OO.#.O....#..#.#...O.O#...#O.O.OO...O..#..OO...O...O...O.....#.O..O#..#.#..OO
+.....O..OO......#.#.#.O.##.OO...O..O.#..#...#OO....OOO......O.OO.#.O..O#O...O.#......OO##O.O.#O..O..
+O##O.#.#..#..OO.O.........#O.#..O.#.##.O#..OOOO..#....O...O.........O..O..###...O...O.#.....O..##.O.
+..O...#O#O.O...O.#..#O.......OO...........#...#..##.O......#..O.O.#OO.OO.#O....#.O.....O..#..#.#..#.
+O#..O..##O#....O..OOO..OO...#O..O.O...O#O...OO.O##.O#O..#......OO##O.##...OOO.O..#....O##O..#......#
+..#O...O..O.O...#..O.O...#O.....O.O......##OO#..O......#..O.#.O......OO.#O........O.....OO...O...O.O
+........OO.#.OO..O......#...#...#..OOOO.OO.#....O.OO...O.##.....O.O....#O.#.OO..##.##..#.#O#.OO...O#
+....#......#O.OO.....OOO....OO..O.O.O....##..O..O.O#.O....O.#O.#O.....O..O........#O.....O.O.....O#.
+#.O#.O#......##.....O.#O...###...##....#O#.#.#....OO...O..#.O....O..#..#..O..........O......#.O.O...
+.O.#..O#.OO....O.#...#O....#....OO......#O.O..#O..........O.#..#...#OOO........#.#.........O.#..O...
+#OO.OO..O..O.O.#O.O.....O.##..#.O#..#.O....#........#.OOO#.#.....#.#.......O#..##..#.OO....O#O#.....
+.......#O.O....#.OOO..OO...O...#....O..#.#....OO..O....O.#.O.#O#..O#.#.O..O......##...OO..#....O.#..
+.O..O#.#OO.O.O.O.##...O..O.O..O.##O...#.O..O..O..O..O.....O...#..OO#O..O###...#...#....O##.OO...#...
+#O....#...##..O..#...#OO.O.O.#......O...O.#.#O..O...O....OOO..O.O..O...O.OO...O...#..O....O#.###....
+....#..O.....##.O.......##.##..OOO.O.#.#.....#....O..#..O....#....O...#.O..O#..O##...#.##....O.#OO##
+O....O...OO.O........#..O...#..#.....O......O.O.OO.OO..#....O..O.............##.O.....##O#.OOO......
+........#.O.####O.OO.#.O..O.O.#.#....OO#.......O..#....##.OOO..O.O.O..#.O.#...O.O.O..O.##O..O#....O.
+...#....#.....O....O.O.O##.O..#O.OO...#.##.O..###OO##.O......#..##.OO...O.......O.......#..O.#.O..O.
+.O.O...O......OO.#....#O..O.O.O..OO.O..O##O...O....O..OO.#..O....O..#.O..OO.OO....O#O..#.O..#O...#.#
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+.#...O.OO#O.O..O.##O..O#...##...O....OO.O#....#...#O.O#....O..........#....#............##.......#..
+.O.#........##O...#O..O..O....OO#O....#.O..OO.##..O..OO#.###OO.....#..#.......O.#.....OO........OO.#
+.OO...O.#..##.....OO..O.O.O.#.###.##.O.#..O..#..O..O...##.#......O....O.O.........O..#.O.O#O.#O...#.
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+.O#.O.#..O..O#...OO...O...O#...O..O..#.O..#...O#.#....O......O#...O...OO.O##.#O....O....#OO....#O...
+OO..OOO.O......OO...OO#O...#.#.#O.OOO#....#.OO#.#.O.#......O.O.OO#..O..#..O.O#.O#.O....O..O...O.....
+...OO....O...#OO#..#..O.#O#....O.....OO.O.#.OO##.....#..O#.OO..#.#.O#..#..O.#..O....#....O.#O...OO#O
+..#.......OO..##.O#...O#....O.#.O..##..#O.......#O#......O..O.........O#..#OO..O..#O.#.#.O.O#.#OO#.O
+...#O#...O...OO...OO..OO...#OO...O...##.O....##.#O##.O....#..O#..O.....O.......###.#.OO#...O......#.
+.O.OO#O##O##...#..#....#..#O...O#..O.O##......#........#O.........#.O....O..#..O.....O..#......O.#.#
+..#....#.O.O.O..O.....O.O#O.O..#......O............O.........O#.O....#.O#..O..O.#OO.....#......O...#
+OO...#..O..O##.#.#O.O.#.#....O....O...O.#..O##...O...#.O...#.O.OO...#........O#O..O.O.O..O.....#.O..
+.OOO....#...O..O.....O..O...O...O..O...O#...#O....O.O...#..OO##.O.#..O..........O#..#..#..OO#.....#.
+O..#..O#....#O..##O..#.#.......OO..O..#...O....O.#....O..O.##........O...O..OO...#....OO#..O.#.#.#..
+O#O.O.O#.#OO#..OO.O.#......#.....#.......##.O..#.O..#..OO..O.#.#.O.O.O#.#......O....####OO#.#O#OO.#.
+.#.....O#..O#O#..OO...#.O.#....#.#..##....O##....#.........##OO...##...O......#.OO...#O....O.O.O#O..
+O......#.O....O...O.....OO.#....#O.##....#.O.O...O..#...O....#.O....O.O....#.OO.#.......#...#..#...O
+...#OO..#......#..OO.O.O.##.O....O.##O##.OO#O.O.O..O.#O#O.OO...........O...###.#......O..#..#O#..OOO
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+.OO.##...#O..O#....O....#..O#....#.....O...O#.....OOO#.....................#..#..#..#O.......O.#OO..
+.#OO..O....O..#.....#O...OO.#....#.#.O...O.#........O...O..O..OO#..#.....#.......OOOOO.OO....O....O.
+.O#...#.......O.O...O.O.O#...OO.O#...O#O.O.#......#......O..O##.##.....O.....##...........O#...O....
+.#.O.O#.....O.#..OO......#O.#..O..O.O.O..#.#...O##.#O..OOO......#...#..OO...O.#.....#O.OOO...#.O..##
+.........O..##OO.#OOOO.O.O..OOO...OO.#.....#...O.#O##..O#..#.#..#...#..O.O...#OO.O...O...#O...#..#..
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+......O.#...O.....O.O..O#...O.#........#.O...O.O....#..O#....O.#.O.O....O...#OO...#........OO..O.O.O
+....O.O..OO.....#...OOOO.O#............O#OO....OOOOOO..#..#O#..#.#.O.OO.#O.....O.#......##..O#..#O..
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+.O.#.O.OO..O#.O#OO..........O.......O..#..#.#..O...#...##.....####...#........##O.......#....#...O##
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+.....#OO.#O........O#....O.#OO.OO........#.O....O.OOOOOO.#.#O......O.#...O#.O.O..OO.....O.OO...#.O.#
+.....#................OO..OOOO..#.....O.###O.O...O..#O..........OO.#...OO.O#...O......O..OOOO.#..###
+O.....O...#O.#..........#O......O..OOO#....O.OOOO....O..#..#O....O.....O#..O..#.O.O....#OO.#....#O..

2023/go/day15/day15.go

@@ -0,0 +1,80 @@
+package day15
+
+import (
+	"adventofcode2023/utils"
+	_ "fmt"
+	"strings"
+)
+
+type Lens struct {
+	label	string
+	fl		int
+}
+
+func Part1(input string) int {
+	ans := 0
+	seqs := strings.Split(input, ",")
+	for _,seq := range seqs {
+		ans += hash(seq)
+	}
+	
+	return ans
+}
+
+func Part2(input string) int {
+	Boxes := [256][]Lens{}
+	cmds := strings.Split(input, ",")
+	for _,cmd := range cmds {
+		if cmd[len(cmd)-1] == '-' {
+			label := cmd[:len(cmd)-1]
+			hash := hash(label)
+			nl := []Lens{}
+			for _, lens := range Boxes[hash] {
+				if lens.label != label {
+					nl = append(nl, lens)
+				}
+			}
+			Boxes[hash] = nl
+		} else {
+			tokens := strings.Split(cmd, "=")
+			label := tokens[0]
+			fl := utils.MustAtoi(tokens[1])
+			hash := hash(label)
+			nl := []Lens{}
+			if len(Boxes[hash]) == 0 {
+				Boxes[hash] = append(Boxes[hash], Lens{label:label, fl:fl})
+			} else {
+				found := false
+				for _, lens := range Boxes[hash] {
+					if lens.label == label {
+						nl = append(nl, Lens{label:label, fl:fl})
+						found = true
+					} else {
+						nl = append(nl, lens)
+					}
+				}
+				Boxes[hash] = nl
+				if ! found {
+					Boxes[hash] = append(Boxes[hash], Lens{label:label, fl:fl})
+				}
+			}
+		}
+	}
+	ans := 0
+	for i, box := range Boxes {
+		for j, lens := range box {
+			ans += (i+1) * (j +1) * lens.fl
+		}
+	} 
+		return ans
+}
+
+func hash(in string) int {
+	result := 0
+	for _, letter := range in {
+		result += int(letter) 
+		result = result * 17
+		result = result % 256
+	}
+	return result
+}

2023/go/day15/day15_test.go

@@ -0,0 +1,17 @@
+package day15
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1("rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7")
+	require.Equal(t, 1320, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2("rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7")
+	require.Equal(t, 145, r)
+}

2023/go/day16/day16.go

@@ -0,0 +1,202 @@
+package day16
+
+import (
+	_ "adventofcode2023/utils"
+	"adventofcode2023/utils/grid2d"
+	_ "adventofcode2023/utils/grid2d"
+	"adventofcode2023/utils/inputs"
+	"fmt"
+	_ "strings"
+)
+
+type Tile struct {
+	object rune
+	energized int
+}
+
+type Beam struct {
+	dir rune
+	r int
+	c int
+	rm bool
+}
+
+var startBeams []Beam
+
+func Part1(input string) int {
+	beams := []Beam{}
+	beams = addBeam(beams, Beam{'s', 0, 3, false})
+	grid := inputs.ToGrid2D[Tile](input, "\n", "", Tile{}, func(c string) Tile { return Tile{ object: rune(c[0]), energized: 0}})
+	return score(grid, beams)
+}
+
+func Part2(input string) int {
+	grid := inputs.ToGrid2D[Tile](input, "\n", "", Tile{}, func(c string) Tile { return Tile{ object: rune(c[0]), energized: 0}})
+	G := grid.Matrix()
+	R := len(G)
+	C := len(G[0])
+	ans := 0
+	for r:=0;r<R;r++{
+		beams := []Beam{}
+		grid := inputs.ToGrid2D[Tile](input, "\n", "", Tile{}, func(c string) Tile { return Tile{ object: rune(c[0]), energized: 0}})
+		beams = addBeam(beams, Beam{'e', r, 0, false})
+		ans = max(ans, score(grid, beams))
+		beams = []Beam{}
+		beams = addBeam(beams, Beam{'w', r, C-1, false})
+		grid = inputs.ToGrid2D[Tile](input, "\n", "", Tile{}, func(c string) Tile { return Tile{ object: rune(c[0]), energized: 0}})
+		ans = max(ans, score(grid, beams))
+	}
+	for c:=0;c<C;c++{
+		beams := []Beam{}
+		grid := inputs.ToGrid2D[Tile](input, "\n", "", Tile{}, func(c string) Tile { return Tile{ object: rune(c[0]), energized: 0}})
+		beams = addBeam(beams, Beam{'s', 0, c, false})
+		ans = max(ans, score(grid, beams))
+		beams = []Beam{}
+		beams = addBeam(beams, Beam{'n', R-1, c, false})
+		grid = inputs.ToGrid2D[Tile](input, "\n", "", Tile{}, func(c string) Tile { return Tile{ object: rune(c[0]), energized: 0}})
+		ans = max(ans, score(grid, beams))
+	}
+
+	return ans
+}
+
+func max(a, b int) int {
+    if a > b {
+        return a
+    }
+    return b
+}
+
+func score(grid *grid2d.Grid[Tile], beams []Beam) int {
+	fmt.Println(grid.StringWithFormatter(func(t Tile, x int, y int) string { return string(t.object)}))
+	G := grid.Matrix()
+	R := len(G)
+	C := len(G[0])
+	fmt.Println("r:", R, "c:", C, "tiles:", R*C )
+	for i:=0;i<1000;i++ {
+		beams = rmBeams(beams)
+		fmt.Println(i, ":", len(beams), ":", energy(G))
+		for i, _ := range beams {
+			r := beams[i].r
+			c := beams[i].c
+			if r >= 0 && r < R && c >= 0 && c < C {
+				G[r][c].energized++
+				switch beams[i].dir {
+				case 'n':
+						tile := &G[r][c]
+						switch tile.object {
+						case '.':
+							beams[i].r--
+						case '|':
+							beams[i].r--
+						case '-':
+							beams[i].dir = 'e'
+							beams[i].c++
+							beams = addBeam(beams, Beam{'w', beams[i].r, beams[i].c-1, false})
+						case '\\':
+							beams[i].dir = 'w'
+							beams[i].c--
+						case '/':
+							beams[i].dir = 'e'
+							beams[i].c++
+						}
+				case 'e':
+						tile := &G[r][c]
+						switch tile.object {
+						case '.':
+							beams[i].c++
+						case '-':
+							beams[i].c++
+						case '|':
+							beams[i].dir = 'n'
+							beams[i].r--
+							beams = addBeam(beams, Beam{'s', beams[i].r+1, beams[i].c, false})
+						case '\\':
+							beams[i].dir = 's'
+							beams[i].r++
+						case '/':
+							beams[i].dir = 'n'
+							beams[i].r--
+						}
+				case 's':
+						tile := &G[r][c]
+						switch tile.object {
+						case '.':
+							beams[i].r++
+						case '|':
+							beams[i].r++
+						case '-':
+							beams[i].dir = 'e'
+							beams[i].c++
+							beams = addBeam(beams, Beam{'w', beams[i].r, beams[i].c-1, false})
+						case '\\':
+							beams[i].dir = 'e'
+							beams[i].c++
+						case '/':
+							beams[i].dir = 'w'
+							beams[i].c--
+						}
+				case 'w':
+						tile := &G[r][c]
+						switch tile.object {
+						case '.':
+							beams[i].c--
+						case '-':
+							beams[i].c--
+						case '|':
+							beams[i].dir = 'n'
+							beams[i].r--
+							beams = addBeam(beams, Beam{'s', beams[i].r+1, beams[i].c, false})
+						case '\\':
+							beams[i].dir = 'n'
+							beams[i].r--
+						case '/':
+							beams[i].dir = 's'
+							beams[i].r++
+						}
+				}
+			} else {
+				beams[i].rm = true
+			}
+		}
+		fmt.Println(grid.StringWithFormatter(func(t Tile, x int, y int) string { if t.energized > 0 {return "#"}; return "."}))
+	}
+	fmt.Println(grid.StringWithFormatter(func(t Tile, x int, y int) string { if t.energized > 0 {return "#"}; return "."}))
+	return energy(G)
+}
+
+func rmBeams(slice []Beam) []Beam {
+    var result []Beam
+
+    for _, value := range slice {
+        if ! value.rm {
+            result = append(result, value)
+        }
+    }
+    return result
+}
+
+func addBeam(beams []Beam, beam Beam) []Beam {
+    for _, value := range startBeams {
+        if value == beam { return beams }
+    }
+	startBeams = append(startBeams, beam)
+	for _, value := range beams {
+        if value == beam { return beams }
+    }
+    return append(beams, beam)
+}
+
+func energy(G [][]Tile) int {
+	ans := 0
+	R := len(G)
+	C := len(G[0])
+	for r:=0;r<R;r++ {
+		for c:=0;c<C;c++ {
+			if G[r][c].energized > 0 {
+				ans++
+			}
+		}
+	}
+	return ans
+}

2023/go/day16/day16.py

@@ -0,0 +1,68 @@
+#!/usr/bin/python3
+import sys
+import re
+from copy import deepcopy
+from math import gcd
+from collections import defaultdict, Counter, deque
+D = open(sys.argv[1]).read().strip()
+L = D.split('\n')
+G = [[c for c in row] for row in L]
+
+R = len(G)
+C = len(G[0])
+
+DR = [-1, 0, 1, 0]
+DC = [ 0, 1, 0,-1]
+
+def step(r,c,d):
+  return (r+DR[d], c+DC[d], d)
+
+def score(sr,sc,sd):
+  POS = [(sr,sc,sd)]
+  SEEN = set()
+  SEEN2 = set()
+  while True:
+    NP = []
+    if not POS:
+      break
+    for (r,c,d) in POS:
+      #print(r,c,d)
+      if 0<=r<R and 0<=c<C:
+        SEEN.add((r,c))
+        if (r,c,d) in SEEN2:
+          continue
+        SEEN2.add((r,c,d))
+        ch = G[r][c]
+        if ch=='.':
+          NP.append(step(r,c,d))
+        elif ch=='/':
+          # up right down left
+          NP.append(step(r,c,{0:1, 1:0, 2:3, 3:2}[d]))
+        elif ch=='\\':
+          NP.append(step(r,c,{0:3, 1:2, 2:1, 3:0}[d]))
+        elif ch=='|':
+          if d in [0,2]:
+            NP.append(step(r,c,d))
+          else:
+            NP.append(step(r, c, 0))
+            NP.append(step(r, c, 2))
+        elif ch=='-':
+          if d in [1,3]:
+            NP.append(step(r,c,d))
+          else:
+            NP.append(step(r, c, 1))
+            NP.append(step(r, c, 3))
+        else:
+          assert False
+    POS = NP
+  return len(SEEN)
+
+print(score(0,0,1))
+ans = 0
+for r in range(R):
+  ans = max(ans, score(r,0,1))
+  ans = max(ans, score(r,C-1,3))
+for c in range(C):
+  ans = max(ans, score(0,c,2))
+  ans = max(ans, score(R-1,c,0))
+print(ans)

2023/go/day16/day16_test.go

@@ -0,0 +1,37 @@
+package day16
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(
+`.|...\....
+|.-.\.....
+.....|-...
+........|.
+..........
+.........\
+..../.\\..
+.-.-/..|..
+.|....-|.\
+..//.|...`)
+	require.Equal(t, 46, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(
+`.|...\....
+|.-.\.....
+.....|-...
+........|.
+..........
+.........\
+..../.\\..
+.-.-/..|..
+.|....-|.\
+..//.|...`)
+	require.Equal(t, 51, r)
+}

2023/go/day16/input.txt

@@ -0,0 +1,110 @@
+\.......................\..........................................-..................-.../................-..
+....../.......\...-......-.|...\..............\.................|............././....-........................
+...............-...-........................................\......\..-.............|......-....\....-........
+..\..|.|...........................-.|........................................./.|....|................|......
+|../................|............................................................\........../..\..............
+........\............../................/..........................\...\....|............./....-.........\\...
+.................-...-...................\../........-|.................../......-...........|................
+........-............/...|-............-.....\.|..............-....-../\../..................\...\././........
+........................-|................................................................-........-..........
+-......./.................|.....\.................\.....//............-........./..../....|...................
+....-.............-........-..........-|.......|...../...\...................\.....................|..........
+...|...\.........|.................|.....|....-....\.......\./........................-.../..../.....-........
+....|....-.-..............\.........|.......................-.......-..............\................/.........
+.....|.\...........-.................-.-........../...\............|...............|...|......./.......|...../
+.....\.........................-.../..-./...\...................../......\...-.......|.\........-|............
+............|.....................................-....../....\.............../-...|...\..\................./.
+......-./|....../............|.........\............-../...-......./.\..\....../......|/...\..................
+................................|.......|..-..../.............................../.-..................-..-/..|.
+...............................-......./......................|./...............-............./....../........
+..................../....................\........\...........................-............/.../..............
+.|||......../.................|.................../..\............................-......./..|...|/.-.........
+......-......./\....../.........|....../.......-...............|.\........-............/.../..................
+.....................-.\/|................//.../.........|.|......\.-..|.........|.........\..................
+.........................\/.......|.|............................|........|.............................././..
+.................................|.................\../..|/.................\.................-...-........-/.
+......................-...-.........../...........................\....\......-..-.......\.-....\....|........
+......-......../..............\/..................\..|........-..............|...-...../......|...............
+|.......|.../....|..............//.....................|..........|/......../................|................
+...|.|..................../|..../.-.......-...........|.....|./....\......-......-................|...........
+......\/./.|\..../|.|..|..........-....|...........|.-.|...................-.\.....|....................\.....
+......../.\......................|.....|...........|.........../.......|....|...|.......-......../......\...-.
+...|...-...||......-..|..-...........|.-.................|.................................-..................
+..............-.\.-........|......\..........................................\./.\........../.....|...........
+../\.........|...............|............|.\/.-/.................-....|...-.................-.....|..../.....
+....................../......../..../-.....\........................\..-.\....|....-.........../-.............
+.................................|................|.........|................../|.....|....\\............/.\..
+...///./.....\.................|/.....................\...................-............|................|.....
+............-...........................--........\................/.............-\................\.....-.../
+...............\.........../|............................|.....................\...-...\.....................-
+...\.............|.............|................\............\|...../...|.........................|...........
+..................|......|..........-.-..............\.........................\..............................
+....-................../.........../...|................/...............|./.|.../....\..../......./......//...
+...../....../..............................|...\../..........-..........-........-..//..../...................
+...............-......|......................|./........./............/..-...........|../.....-........-./....
+..\.........................|...-.......\.................|..............-........\....-.............-....|...
+.......|......|....../........\...........|......-........../......-..................../....................\
+.......................|....-..|........./.|.-...............|..\......\.....-.......\...-/....|/.........\...
+\......\..-.....................\..........................\................................../...........\...
+-....-......../............................................................../.\.......|..............|....-..
+........|......................|.............-....\................................./..\.......|..........-...
+...-...............|........./......\...../.......|...|...............\.../...\.../......|.....-.\......\.....
+............./.....|......................|.....................................\...||.................-....|.
+./.....-................/........|./....-......../......./..............\..................................\..
+.../..../\........-..........................|.-/.|..\................\\-.......|......./...||.......|........
+.....-.........................-...............\...........|.............-.\.../.|......-.|......../...-.....-
+......\....................|...../......................|.../......-..|............|......./.../.........|....
+...|...........-....................................../.|............./....|..../........./.....\../..........
+....../.../................\........................\...\....\......\............../|...............\.-.......
+./....\.../.............|............................-.../............../............/...........\...|........
+............................|.................|/..........//.........../..-...............|...................
+.....\......\.................|.....|...\-./...............\................|....../.....-..\........-....-...
+........................./-........\................./........-/.|....-.......\............-/\......|.\...-...
+..../../..|.|...............\.......................................-.........................................
+...........|...................................................-...-......|..................\............../.
+/....|......................................................................|\.../.......-...........-...|....
+......|.-.\......-........|.....-..|.\..............-......./......-|.........................-...............
+............\......................................|........................|.-...............................
+.........-.........../....\./....../.-...-..//.........../.......\\...........................................
+........\......../............./...-......\.../..|..|............................../......../..\..............
+--.........|.....-...|............../...|.......|..............\|............|.........................|.-....
+-\......./..............-....-....\...|.-........\/.\./............-/...\........|-.........../../...\........
+.\|\..............-......-.\...-....\..........................\........|...........-......./.............../.
+..........................|...\..../.../..........\.............-...//...............\..................-.....
+........./..........................\............|-.....|..-...|......../........-...........................\
+.......\.../.....\....../.......|..|...............-......................|....-...................-.|........
+......|.......\.../..............................-..............................|......-.-...................\
+/.....|.......-............/|.....|-......./..../......-........../..|......../.-..\..../....../...|..........
+............/..--..........-............\.......\................\........................../../....|.........
+..|..-................|.|..|................/.......\............-//.......................\..\...............
+.......................-......-..................|....\................-......\.|....\....|..../../|.-........
+........................-..................-...........................-..-................-................|.
+/.\....|.-.................................\..-.....\./.........../-.|..............\..\.....--|/....\........
+.......-..-../..................\..--|..............|...............|\........|...--................|./.\.....
+..........|................-.......|..................................................|...................|...
+-.-..|....-.|........-./...|.-.........\.....\/........-........\........../................./.../........\...
+..................../...|/......................................../............\.|./../................/\|....
+...//.........................\....../..............\../.......-..\....|......................................
+............................./..|./../.........-/..\..........................................................
+......\.....|..................|..................\.....\.-..\...../............................../...........
+..........\...........-..........-.....-....\/................../.................................\.....|..\..
+..../.\...................................\............\...\....|.................|.....................-.....
+...........-...........................\.......|-../.|....|.....|......................-...../................
+.......|.........\..............|....\...-......../...........-.....-..-...........-..................\...\.|.
+...........|.......................|....-..........\............................\.................../.\.......
+..../.................\.......-..|.................../........................|...............\...........-.|.
+............./..|.-\..../.....-............-....|..\......|......../............-.........|................\..
+...................\...\/......\............|......................\....|...................-./-..............
+..-\...........|.................../.....|....|............................-..|............\.............\....
+.|.....\....\........|..................\...............|..-/.........|.-/...........-............-...........
+.....\...../......-............|........./..|............-........................\....-......................
+......\......../........|..............\...-..-...|.......................................................|...
+...................|.................................\.....\...........................|../.|.-......-........
+..................|..............\.....\............|........../....../...............\.........\.............
+..|...........-..../....\.........--...\................../.............-...-....................-..../....|..
+.|...\...................|......-...........-\..........\.....|.....|..........|.........|....|-../...........
+.............\|...................../\...............\....../.......-....\.....................-..............
+.......//.....................\....\......\......\.........|...................../......../.........\......-..
+.\./.........-...-./-.\.............../......|................................\|....\...../....-..............
+.......|......../......../......./.........../...............|............................../..|......../.....
+............./.........|.....-./.........../....-......./|......-................|............................

2023/go/main.go

@@ -20,6 +20,9 @@ import (
 	"adventofcode2023/day11"
 	"adventofcode2023/day12"
 	"adventofcode2023/day13"
+	"adventofcode2023/day14"
+	"adventofcode2023/day15"
+	"adventofcode2023/day16"
 
 	
 
@@ -70,6 +73,15 @@ func main() {
 	case 13:
 		fmt.Printf("part 1: %d\n", day13.Part1(utils.Readfile(d)))
 		fmt.Printf("part 2: %d\n", day13.Part2(utils.Readfile(d)))
+	case 14:
+		fmt.Printf("part 1: %d\n", day14.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day14.Part2(utils.Readfile(d)))
+	case 15:
+		fmt.Printf("part 1: %d\n", day15.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day15.Part2(utils.Readfile(d)))
+	case 16:
+		fmt.Printf("part 1: %d\n", day16.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day16.Part2(utils.Readfile(d)))
 	default:
 		panic(fmt.Errorf("no such day: %d", d))
 	}
@@ -77,7 +89,7 @@ func main() {
 
 // Reads day from os.Args.
 func day() int {
-	latest := 12
+	latest := 15
 	if len(os.Args) == 1 {
 		return latest
 	}

2024/go/.vscode/launch.json

@@ -0,0 +1,16 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Package",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "args": ["16"],
+            "program": "${fileDirname}"
+        }
+    ]
+}

2024/go/day01/day01.go

@@ -0,0 +1,54 @@
+package day01
+
+import (
+	"adventofcode2024/utils"
+	"sort"
+	"strings"
+)
+
+func Part1(input string) int {
+	var list1, list2 []int
+
+	num := 0
+	lines := strings.Split(input, "\n")
+	for _, line := range lines {
+		fields := strings.Fields(line)
+		// Convert the fields to integers
+		val1 := utils.MustAtoi(fields[0])
+		val2 := utils.MustAtoi(fields[1])
+
+		// Append to the respective slices
+		list1 = append(list1, val1)
+		list2 = append(list2, val2)
+	}
+	sort.Ints(list1)
+	sort.Ints(list2)
+	for i := 0; i < len(list1); i++ {
+		num += utils.Abs(list1[i] - list2[i])
+	}
+	return num
+
+}
+
+func Part2(input string) int {
+	var list1 []int
+	list2 := make(map[int]int)
+
+
+	num := 0
+	lines := strings.Split(input, "\n")
+	for _, line := range lines {
+		fields := strings.Fields(line)
+		// Convert the fields to integers
+		val1 := utils.MustAtoi(fields[0])
+		val2 := utils.MustAtoi(fields[1])
+
+		// Append to the respective slices
+		list1 = append(list1, val1)
+		list2[val2]++
+	}
+	for i := 0; i < len(list1); i++ {
+		num += list1[i] * list2[list1[i]]
+	}
+	return num
+}

2024/go/day01/day01_test.go

@@ -0,0 +1,17 @@
+package day01
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1("")
+	require.Equal(t, 0, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2("")
+	require.Equal(t, 0, r)
+}

2024/go/go.mod

@@ -0,0 +1,5 @@
+module adventofcode2024
+
+go 1.19
+
+require golang.org/x/exp v0.0.0-20221208152030-732eee02a75a

2024/go/go.sum

@@ -0,0 +1,2 @@
+golang.org/x/exp v0.0.0-20221208152030-732eee02a75a h1:4iLhBPcpqFmylhnkbY3W0ONLUYYkDAW9xMFLfxgsvCw=
+golang.org/x/exp v0.0.0-20221208152030-732eee02a75a/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=

2024/go/main.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"fmt"
+//	"math/rand"
+	"os"
+//	"strings"
+//	"time"
+	"adventofcode2024/utils"
+	"adventofcode2024/day01"
+)
+// Usage: go run main.go <NN>
+// assumes input is in day<NN>/input.txt
+func main() {
+	d := day()
+	fmt.Printf("Running day %02d\n", d)
+
+	switch d {
+	case 1:
+		fmt.Printf("part 1: %d\n", day01.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day01.Part2(utils.Readfile(d)))
+	default:
+		panic(fmt.Errorf("no such day: %d", d))
+	}
+}
+
+// Reads day from os.Args.
+func day() int {
+	latest := 1
+	if len(os.Args) == 1 {
+		return latest
+	}
+
+	if os.Args[1] == "next" {
+		genNext(latest + 1)
+		os.Exit(0)
+	}
+	day := utils.MustAtoi(os.Args[1])
+	return day
+}
+
+
+func genNext(n int) {
+	os.Mkdir(fmt.Sprintf("day%02d", n), 0755)
+	f, err := os.Create(fmt.Sprintf("day%02d/day%02d.go", n, n))
+	utils.PanicOnErr(err)
+	defer f.Close()
+	f.WriteString(fmt.Sprintf(`package day%02d
+
+func Part1(input string) int {
+	return 0
+}
+
+func Part2(input string) int {
+	return 0
+}
+`, n))
+	fmt.Printf("wrote day%02d/day%02d.go\n", n, n)
+
+	f, err = os.Create(fmt.Sprintf("day%02d/day%02d_test.go", n, n))
+	utils.PanicOnErr(err)
+	defer f.Close()
+	f.WriteString(fmt.Sprintf(`package day%02d
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1("")
+	require.Equal(t, 0, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2("")
+	require.Equal(t, 0, r)
+}
+`, n))
+	fmt.Printf("wrote day%02d/day%02d_test.go\n", n, n)
+	utils.GenInputFile(n)
+
+}

2024/go/utils/grid2d/grid2d.go

@@ -0,0 +1,77 @@
+package grid2d
+
+import (
+	"strings"
+
+	"adventofcode2024/utils"
+)
+
+type Grid[T any] struct {
+	sizeX, sizeY int
+	matrix       [][]T
+	empty        T
+}
+
+func NewGrid[T any](sizeX, sizeY int, empty T) *Grid[T] {
+	matrix := make([][]T, sizeY)
+	rows := make([]T, sizeX*sizeY)
+	for i := 0; i < sizeX*sizeY; i++ {
+		rows[i] = empty
+	}
+
+	j := 0
+	for i := 0; i < sizeY; i++ {
+		matrix[i] = rows[j : j+sizeX : j+sizeX]
+		j += sizeX
+	}
+	return &Grid[T]{
+		sizeX:  sizeX,
+		sizeY:  sizeY,
+		matrix: matrix,
+		empty:  empty,
+	}
+}
+
+func (g *Grid[T]) SizeX() int {
+	return g.sizeX
+}
+
+func (g *Grid[T]) SizeY() int {
+	return g.sizeY
+}
+func (g *Grid[T]) Matrix() [][]T {
+	return g.matrix
+} 
+
+func (g *Grid[T]) Get(x, y int) T {
+	if x < 0 || x >= g.sizeX {
+		return g.empty
+	}
+	if y < 0 || y >= g.sizeY {
+		return g.empty
+	}
+	return g.matrix[y][x]
+}
+
+func (g *Grid[T]) Set(x, y int, v T) {
+	if x < 0 || x >= g.sizeX {
+		panic("invalid x")
+	}
+	if y < 0 || y >= g.sizeY {
+		panic("invalid y")
+	}
+	g.matrix[y][x] = v
+}
+
+func (g *Grid[T]) StringWithFormatter(formatter func(T, int, int) string) string {
+	var r strings.Builder
+	for j := 0; j < g.sizeY; j++ {
+		for i := 0; i < g.sizeX; i++ {
+			_, err := r.WriteString(formatter(g.matrix[j][i], i, j))
+			utils.PanicOnErr(err)
+		}
+		_, err := r.WriteRune('\n')
+		utils.PanicOnErr(err)
+	}
+	return r.String()
+}

2024/go/utils/inputFile.go

@@ -0,0 +1,63 @@
+package utils
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+)
+
+func GenInputFile(day int) string {
+	var d string
+	if day < 10 {
+		d = fmt.Sprintf("0%d", day)
+	} else {
+		d = fmt.Sprintf("%d", day)
+	}
+
+	pwd, _ := os.Getwd()
+	path := fmt.Sprintf("%s/day%s/input.txt", pwd, d)
+	fi, _ := os.Stat(path)
+	if fi != nil {
+		return path
+	}
+
+	fmt.Printf("Creating new input file %v...", path)
+	f, err := os.Create(path)
+	if err != nil {
+		fmt.Println(err)
+	} else {
+		defer f.Close()
+		data := readHttp(2024, day)
+		_, err := f.WriteString(data)
+		if err != nil {
+			fmt.Println(err)
+		}
+	}
+	return path
+}
+
+func readHttp(year, day int) string {
+	fmt.Println("Fetching data into file...")
+
+	url := fmt.Sprintf("https://adventofcode.com/%d/day/%d/input", year, day)
+	session := os.Getenv("sessionAoC")
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		panic(err)
+	}
+
+	req.AddCookie(&http.Cookie{Name: "session", Value: session})
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		panic(err)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		panic(err)
+	}
+	return string(body)
+}
+

2024/go/utils/inputs/inputs.go

@@ -0,0 +1,45 @@
+package inputs
+
+import (
+	"strings"
+
+	"adventofcode2024/utils"
+	"adventofcode2024/utils/grid2d"
+	sparsegrid "adventofcode2024/utils/sparseGrid"
+)
+
+func ToInts(input string, sep string) []int {
+	var r []int
+	for _, line := range strings.Split(input, sep) {
+		if line != "" {
+			r = append(r, utils.MustAtoi(line))
+		}
+	}
+	return r
+}
+
+func ToGrid2D[T any](input, rowSep, colSep string, empty T, conv func(string) T) *grid2d.Grid[T] {
+	lines := strings.Split(input, rowSep)
+
+	grid := grid2d.NewGrid(len(lines[0]), len(lines), empty)
+	for y, line := range lines {
+		for x, v := range strings.Split(line, colSep) {
+			grid.Set(x, y, conv(v))
+		}
+	}
+
+	return grid
+}
+
+func ToSparseGrid[T comparable](input, rowSep, colSep string, empty T, conv func(string) T) *sparsegrid.SparseGrid[T] {
+	lines := strings.Split(input, rowSep)
+
+	grid := sparsegrid.NewGrid(empty)
+	for y, line := range lines {
+		for x, v := range strings.Split(line, colSep) {
+			grid.Set(x, y, conv(v))
+		}
+	}
+
+	return grid
+}

2024/go/utils/sparseGrid/sparseGrid.go

@@ -0,0 +1,81 @@
+package sparsegrid
+
+import (
+	"fmt"
+	"strings"
+
+	"adventofcode2024/utils"
+)
+
+type SparseGrid[T comparable] struct {
+	minX, maxX, minY, maxY int
+	data                   map[string]T
+	empty                  T
+}
+
+func NewGrid[T comparable](empty T) *SparseGrid[T] {
+	return &SparseGrid[T]{
+		minX:  utils.MaxInt,
+		maxX:  utils.MinInt,
+		minY:  utils.MaxInt,
+		maxY:  utils.MinInt,
+		data:  map[string]T{},
+		empty: empty,
+	}
+}
+
+func (g *SparseGrid[T]) SizeX() (int, int) {
+	return g.minX, g.maxX
+}
+
+func (g *SparseGrid[T]) SizeY() (int, int) {
+	return g.minY, g.maxY
+}
+
+func (g *SparseGrid[T]) Visited() int {
+	return len(g.data)
+}
+
+func (g *SparseGrid[T]) Get(x, y int) T {
+	k := key(x, y)
+	v, ok := g.data[k]
+	if !ok {
+		return g.empty
+	}
+	return v
+}
+
+func (g *SparseGrid[T]) Set(x, y int, v T) {
+	k := key(x, y)
+	current, ok := g.data[k]
+	if ok && v == current {
+		return
+	} else if !ok && v == g.empty {
+		return
+	} else if v == g.empty {
+		delete(g.data, k)
+	} else {
+		g.data[k] = v
+		g.minX = utils.Min(g.minX, x)
+		g.maxX = utils.Max(g.maxX, x)
+		g.minY = utils.Min(g.minY, y)
+		g.maxY = utils.Max(g.maxY, y)
+	}
+}
+
+func (g *SparseGrid[T]) StringWithFormatter(formatter func(T, int, int) string) string {
+	var r strings.Builder
+	for j := g.minY; j <= g.maxY; j++ {
+		for i := g.minX; i <= g.maxX; i++ {
+			_, err := r.WriteString(formatter(g.Get(i, j), i, j))
+			utils.PanicOnErr(err)
+		}
+		_, err := r.WriteRune('\n')
+		utils.PanicOnErr(err)
+	}
+	return r.String()
+}
+
+func key(x, y int) string {
+	return fmt.Sprintf("%d:%d", x, y)
+}

2024/go/utils/utils.go

@@ -0,0 +1,222 @@
+package utils
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"reflect"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"golang.org/x/exp/constraints"
+)
+
+func PanicOnErr(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+const MaxInt = int(^uint(0) >> 1)
+const MinInt = ^MaxInt
+
+func Max[T constraints.Ordered](a, b T) T {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func Min[T constraints.Ordered](a, b T) T {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func SliceMinMax[T constraints.Ordered](slice []T) (*T, *T) {
+	if len(slice) == 0 {
+		return nil, nil
+	}
+	min := &slice[0]
+	max := &slice[0]
+	for i, v := range slice {
+		if v < *min {
+			min = &slice[i]
+		}
+		if v > *max {
+			max = &slice[i]
+		}
+	}
+	return min, max
+}
+
+func MustAtoi(s string) int {
+	v, err := strconv.Atoi(s)
+	PanicOnErr(err)
+	return v
+}
+
+// Returns key from map[T]int which has the max value
+func MapFindMax(m interface{}) interface{} {
+	var maxK interface{} = nil
+	var maxV = MinInt
+	iter := reflect.ValueOf(m).MapRange()
+	for iter.Next() {
+		k := iter.Key()
+		v := int(iter.Value().Int())
+		if v > maxV {
+			maxV = v
+			maxK = k.Interface()
+		}
+	}
+	return maxK
+}
+
+// Returns key from map[T]int which has the min value
+func MapFindMin(m interface{}) interface{} {
+	var minK interface{} = nil
+	var minV = MaxInt
+	iter := reflect.ValueOf(m).MapRange()
+	for iter.Next() {
+		k := iter.Key()
+		v := int(iter.Value().Int())
+		if v < minV {
+			minV = v
+			minK = k.Interface()
+		}
+	}
+	return minK
+}
+
+func Readfile(day int) string {
+	filename := fmt.Sprintf("day%02d/input.txt", day)
+	file, err := os.Open(filename)
+	PanicOnErr(err)
+	defer file.Close()
+
+	reader := bufio.NewReader(file)
+	contents, err := io.ReadAll(reader)
+	PanicOnErr(err)
+
+	return strings.TrimSuffix(string(contents), "\n")
+}
+
+func ReadfileAsSlice(day int) []string {
+	filename := fmt.Sprintf("day%02d/input.txt", day)
+	file, err := os.Open(filename)
+	PanicOnErr(err)
+	defer file.Close()
+
+	arr := make([]string, 0)
+	sc := bufio.NewScanner(file)
+	for sc.Scan() {
+		arr = append(arr, sc.Text())
+	}
+
+	return arr
+}
+
+func ParseToStruct(re *regexp.Regexp, input string, target interface{}) bool {
+	m := re.FindStringSubmatch(input)
+	if m == nil {
+		return false
+	}
+
+	var useOffset bool
+
+	for i, name := range re.SubexpNames() {
+		if i == 0 {
+			continue
+		}
+		var field reflect.Value
+		if name == "" {
+			// use offset
+			if i == 1 {
+				useOffset = true
+			} else if !useOffset {
+				panic("can't mix named and unnamed subexpressions")
+			}
+			field = reflect.ValueOf(target).Elem().Field(i - 1)
+		} else {
+			// use name
+			if i == 1 {
+				useOffset = false
+			} else if useOffset {
+				panic("can't mix named and unnamed subexpressions")
+			}
+			field = reflect.ValueOf(target).Elem().FieldByName(name)
+		}
+		if field.Kind() == reflect.String {
+			field.SetString(m[i])
+		} else if field.Kind() == reflect.Int {
+			v, err := strconv.Atoi(m[i])
+			PanicOnErr(err)
+			field.SetInt(int64(v))
+		} else if field.Kind() == reflect.Uint8 {
+			if len(m[i]) != 1 {
+				panic(fmt.Sprintf("expecting 1 char, got: %s", m[i]))
+			}
+			field.SetUint(uint64(m[i][0]))
+		} else {
+			panic(fmt.Sprintf("unknown kind: %s", field.Kind()))
+		}
+	}
+	return true
+}
+
+func MustParseToStruct(re *regexp.Regexp, input string, target interface{}) {
+	if !ParseToStruct(re, input, target) {
+		panic(fmt.Errorf("failed to parse: %s", input))
+	}
+}
+
+func CharToLower(c byte) byte {
+	return strings.ToLower(string(c))[0]
+}
+
+func CharToUpper(c byte) byte {
+	return strings.ToUpper(string(c))[0]
+}
+
+func Contains(haystack []string, needle string) bool {
+	for _, s := range haystack {
+		if s == needle {
+			return true
+		}
+	}
+	return false
+}
+
+func Abs[T constraints.Signed](x T) T {
+	if x < 0 {
+		return -x
+	}
+	return x
+}
+
+func Gcd(x, y int) int {
+	if x <= 0 || y <= 0 {
+		panic(fmt.Errorf("invalid input: %d, %d", x, y))
+	}
+	if x == y {
+		return x
+	}
+	if x > y {
+		return Gcd(x-y, y)
+	} else {
+		return Gcd(x, y-x)
+	}
+}
+
+func Sign[T constraints.Signed](x T) int {
+	if x < 0 {
+		return -1
+	} else if x > 0 {
+		return 1
+	} else {
+		return 0
+	}
+}