Day01

2025/gareth/day01/day01.go

@@ -0,0 +1,64 @@
+package day01
+
+import (
+	"strconv"
+	"strings"
+)
+
+func Part1(input string) int {
+	lines := strings.Split(input, "\n")
+
+	position := 50
+	output := 0
+
+	for _, line := range lines {
+		direction := line[0]
+		amount, _ := strconv.Atoi(line[1:])
+
+		if direction == 'R' {
+			position += amount
+			for position > 99 {
+				position -= 100
+			}
+		} else if direction == 'L' {
+			position -= amount
+			for position < 0 {
+				position += 100
+			}
+		}
+
+		if position == 0 {
+			output++
+		}
+	}
+
+	return output
+}
+
+func Part2(input string) int {
+	lines := strings.Split(input, "\n")
+	position := 50
+	output := 0
+
+	for _, line := range lines {
+		direction := line[0]
+		amount, _ := strconv.Atoi(line[1:])
+
+		step := 1
+		if direction == 'L' {
+			step = -1
+		}
+
+		for i := 0; i < amount; i++ {
+			position = (position + step) % 100
+			if position < 0 {
+				position += 100
+			}
+			if position == 0 {
+				output++
+			}
+		}
+	}
+
+	return output
+}

2025/gareth/day01/day01_test.go

@@ -0,0 +1,35 @@
+package day01
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(`L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82`)
+	assert.Equal(t, 3, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(`L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82`)
+	assert.Equal(t, 6, r)
+}

2025/gareth/day01/poc.py

@@ -0,0 +1,49 @@
+def part1(input_file):
+    file = open(input_file, "r")
+    line = file.readline()
+
+    position = 50
+    output = 0
+    while line:
+        direction = line[0]
+        amount = int(line[1:])
+
+        if direction == "R":
+            position += amount
+            while position > 99:
+                position -= 100
+
+        elif direction == "L":
+            position -= amount
+            while position < 0:
+                position += 100
+
+        if position == 0:
+            output += 1
+
+        line = file.readline()
+
+    file.close()
+    print("Part 1:", output)
+
+def part2(input_file):
+    position = 50
+    output = 0
+
+    with open(input_file) as file:
+        for line in file:
+            line = line.strip()
+            direction = line[0]
+            amount = int(line[1:])
+
+            step = 1 if direction == "R" else -1
+
+            for _ in range(amount):
+                position = (position + step) % 100
+                if position == 0:
+                    output += 1
+
+    print("Part 2:", output)
+
+part1("input.txt")
+part2("input.txt")

2025/gareth/go.mod

@@ -0,0 +1,11 @@
+module aoc/2025
+
+go 1.23.2
+
+require github.com/stretchr/testify v1.11.1
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

2025/gareth/go.sum

@@ -0,0 +1,9 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

2025/gareth/main.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"aoc/2025/day01"
+	"fmt"
+	"os"
+	"time"
+)
+
+func main() {
+	start := time.Now()
+	data, _ := os.ReadFile("day01/input.txt")
+	fmt.Printf("part 1: %d\n", day01.Part1(string(data)))
+	fmt.Printf("part 2: %d\n", day01.Part2(string(data)))
+	elapsed := time.Since(start)
+	fmt.Printf("Execution time: %s\n", elapsed)
+}