day5

2024/go/day05/day05.go

@@ -0,0 +1,148 @@
+package day05
+
+import (
+	"adventofcode2024/utils"
+	_ "sort"
+	"strings"
+	"fmt"
+)
+
+func Part1(input string) int {
+	num := 0
+	rules := make(map[int][]int)
+
+	sections := strings.Split(input, "\n\n")
+	rules_str := strings.Split(sections[0], "\n")
+	updates_str := strings.Split(sections[1], "\n")
+	updates := make([][]int, len(updates_str)) 
+
+	for _, rule := range rules_str {
+		fields := strings.Split(rule, "|")
+		// Convert the fields to integers
+		val1 := utils.MustAtoi(fields[0])
+		val2 := utils.MustAtoi(fields[1])
+		rules[val1] = append(rules[val1], val2)
+	}
+	for i, update := range updates_str {
+		fields := strings.Split(update, ",")
+		for _, field := range fields {
+			updates[i] = append(updates[i], utils.MustAtoi(field))
+		}
+	}
+	for _, update := range updates {
+		good := true
+		reverseSlice(update)
+		fmt.Printf("rules: %v\n", rules)
+		fmt.Printf("update: %v\n", update)		
+		for i, page := range update {
+			for _, rule := range rules[page] {
+				if contains(update[i+1:], rule) {
+					good = false
+					break
+				}
+			}
+			if !good {
+				break
+			}
+		}
+		if good {
+			fmt.Printf("good: %v\n", update)
+			num += update[len(update)/2]
+		}
+	}
+	return num
+}
+
+func Part2(input string) int {
+	num := 0
+	rules := make(map[int][]int)
+
+	sections := strings.Split(input, "\n\n")
+	rules_str := strings.Split(sections[0], "\n")
+	updates_str := strings.Split(sections[1], "\n")
+	updates := make([][]int, len(updates_str)) 
+
+	for _, rule := range rules_str {
+		fields := strings.Split(rule, "|")
+		// Convert the fields to integers
+		val1 := utils.MustAtoi(fields[0])
+		val2 := utils.MustAtoi(fields[1])
+		rules[val1] = append(rules[val1], val2)
+	}
+	for i, update := range updates_str {
+		fields := strings.Split(update, ",")
+		for _, field := range fields {
+			updates[i] = append(updates[i], utils.MustAtoi(field))
+		}
+	}
+	for _, update := range updates {
+		reverseSlice(update)
+		if !isGood(update, rules) {
+			fmt.Printf("not good: %v\n", update)
+			makeGood(update, rules)
+			fmt.Printf("good: %v\n", update)
+			num += update[len(update)/2]
+		}
+	}
+	return num
+}
+
+func contains(slice []int, x int) bool {
+    for _, value := range slice {
+        if value == x {
+            return true
+        }
+    }
+    return false
+}
+
+func location(slice []int, x int) int {
+    for i, value := range slice {
+        if value == x {
+            return i
+        }
+    }
+    return -1
+}
+
+func reverseSlice(slice []int) {
+    for i, j := 0, len(slice)-1; i < j; i, j = i+1, j-1 {
+        slice[i], slice[j] = slice[j], slice[i]
+    }
+}
+
+func isGood(update []int, rules map[int][]int) bool {
+	good := true
+	for i, page := range update {
+		for _, rule := range rules[page] {
+			if contains(update[i+1:], rule) {
+				good = false
+				break
+			}
+		}
+		if !good {
+			return good
+		}
+	}
+	return good
+}
+
+func makeGood(update []int, rules map[int][]int) []int {
+	for i, page := range update {
+		for _, rule := range rules[page] {
+			loc := location(update[i+1:], rule)
+			if loc != -1 {
+				swap(update, loc+i+1, i)
+				makeGood(update, rules)
+			}
+		}
+	}
+	return update
+}
+
+func swap(slice []int, i, j int) {
+    if i < 0 || i >= len(slice) || j < 0 || j >= len(slice) {
+        panic("Index out of range")
+    }
+    slice[i], slice[j] = slice[j], slice[i]
+}

2024/go/day05/day05_test.go

@@ -0,0 +1,71 @@
+package day05
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(`47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47`)
+	require.Equal(t, 143, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(`47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47`)
+	require.Equal(t, 123, r)
+}

2024/go/main.go

@@ -10,8 +10,8 @@ import (
 	"adventofcode2024/day01"
 	"adventofcode2024/day02"
 	"adventofcode2024/day03"
-	"adventofcode2024/day04"
+	"adventofcode2024/day04"	
-
+	"adventofcode2024/day05"
 )
 // Usage: go run main.go <NN>
 // assumes input is in day<NN>/input.txt
@@ -32,6 +32,9 @@ func main() {
 	case 4:
 		fmt.Printf("part 1: %d\n", day04.Part1(utils.Readfile(d)))
 		fmt.Printf("part 2: %d\n", day04.Part2(utils.Readfile(d)))
+	case 5:
+		fmt.Printf("part 1: %d\n", day05.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day05.Part2(utils.Readfile(d)))
 	default:
 		panic(fmt.Errorf("no such day: %d", d))
 	}
@@ -39,7 +42,7 @@ func main() {
 
 // Reads day from os.Args.
 func day() int {
-	latest := 3
+	latest := 4
 	if len(os.Args) == 1 {
 		return latest
 	}