day11p2 and optimize p1

day11p1/solution.go

@@ -11,34 +11,40 @@ import (
 func Solve(r io.Reader) any {
 	lines := utils.ReadLines(r)
 
-	arrStr := strings.Split(lines[0], " ")
-	arr := make([]int, len(arrStr))
-	for i, s := range arrStr {
-		arr[i], _ = strconv.Atoi(s)
+	stones := make(map[int]int)
+	for _, line := range strings.Split(lines[0], " ") {
+		stone, _ := strconv.Atoi(line)
+		stones[stone] = 1
 	}
 
 	for i := 0; i < 25; i++ {
-		arr = blink(arr)
+		stones = blink(stones)
 	}
 
-	return len(arr)
+	total := 0
+	for _, stone := range stones {
+		total += stone
+	}
+
+	return total
 }
 
-func blink(arr []int) []int {
-    var result []int
-    for _, stone := range arr {
-        stonestr := strconv.Itoa(stone)
-        if stone == 0 {
-            result = append(result, 1)
-        } else if len(stonestr)%2 == 0 {
-            part1 := stonestr[:len(stonestr)/2]
-            part2 := stonestr[len(stonestr)/2:]
-            part1int, _ := strconv.Atoi(part1)
-            part2int, _ := strconv.Atoi(part2)
-            result = append(result, part1int, part2int)
-        } else {
-            result = append(result, stone*2024)
-        }
-    }
-    return result
+func blink(stones map[int]int) map[int]int {
+	result := make(map[int]int)
+	for stone, cnt := range stones {
+		if stone == 0 {
+			result[1] += cnt
+		} else {
+			stonestr := strconv.Itoa(stone)
+			if len(stonestr)%2 == 0 {
+				left, _ := strconv.Atoi(stonestr[:len(stonestr)/2])
+				right, _ := strconv.Atoi(stonestr[len(stonestr)/2:])
+				result[left] += cnt
+				result[right] += cnt
+			} else {
+				result[stone*2024] += cnt
+			}
+		}
+	}
+	return result
 }

day11p2/solution.go

@@ -0,0 +1,50 @@
+package day11p2
+
+import (
+	"io"
+	"strconv"
+	"strings"
+
+	"aoc/utils"
+)
+
+func Solve(r io.Reader) any {
+	lines := utils.ReadLines(r)
+
+	stones := make(map[int64]int64)
+	for _, line := range strings.Split(lines[0], " ") {
+		stone, _ := strconv.ParseInt(line, 10, 64)
+		stones[stone] = 1
+	}
+
+	for i := 0; i < 75; i++ {
+		stones = blink(stones)
+	}
+
+	total := int64(0)
+	for _, stone := range stones {
+		total += stone
+	}
+
+	return total
+}
+
+func blink(stones map[int64]int64) map[int64]int64 {
+	result := make(map[int64]int64)
+	for stone, cnt := range stones {
+		if stone == 0 {
+			result[1] += cnt
+		} else {
+			stonestr := strconv.FormatInt(stone, 10)
+			if len(stonestr)%2 == 0 {
+				left, _ := strconv.Atoi(stonestr[:len(stonestr)/2])
+				right, _ := strconv.Atoi(stonestr[len(stonestr)/2:])
+				result[int64(left)] += cnt
+				result[int64(right)] += cnt
+			} else {
+				result[stone*2024] += cnt
+			}
+		}
+	}
+	return result
+}

day11p2/solution_test.go

@@ -0,0 +1,33 @@
+package day11p2
+
+import (
+	"strings"
+	"testing"
+
+	"aoc/utils"
+)
+
+var testInput = `125 17`
+
+func TestSolve(t *testing.T) {
+	tests := []struct {
+		input  string
+		answer int64
+	}{
+		{testInput, int64(65601038650482)},
+	}
+
+	if testing.Verbose() {
+		utils.Verbose = true
+	}
+
+	for _, test := range tests {
+		r := strings.NewReader(test.input)
+
+		result := Solve(r).(int64)
+
+		if result != test.answer {
+			t.Errorf("Expected %d, got %d", test.answer, result)
+		}
+	}
+}