add 2024/day1

2024/01/main.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"aoc2024/helper"
+	"fmt"
+	"sort"
+)
+
+var list_a, list_b []int
+
+func main() {
+	list_a, list_b = helper.ReadLinesTwoIntSlices()
+
+	// part 1
+	distance := list_distance(list_a, list_b)
+	fmt.Printf("Distance: %v\n", distance)
+
+	// part 2
+	similarity := list_similarity(list_a, list_b)
+	fmt.Printf("Similarity: %v\n", similarity)
+}
+
+func list_distance(list_a []int, list_b []int) (dist int) {
+	sort.Ints(list_a)
+	sort.Ints(list_b)
+
+	for i := range list_a {
+		dist += abs(list_a[i] - list_b[i])
+	}
+	return dist
+}
+
+func abs(x int) int {
+	if x < 0 {
+		return -x
+	}
+
+	return x
+}
+
+func list_similarity(list_a []int, list_b []int) (sim int) {
+	for _, val := range list_a {
+		valcount := countIntInList(list_b, val)
+		sim += valcount * val
+	}
+	return sim
+}
+
+func countIntInList(lst []int, i int) (count int) {
+	for _, val := range lst {
+		if val == i {
+			count++
+		}
+	}
+	return count
+}