feat: solve part one using recursion and memoization

internal/2015/DaySeven/code.go

@@ -0,0 +1,69 @@
+package dayseven
+
+import (
+	"os"
+	"strconv"
+	"strings"
+
+	"advent-of-code/internal/registry"
+)
+
+func init() {
+	registry.Register("2015D7", ParseInput, PartOne, PartTwo)
+}
+
+func ParseInput(filepath string) []string {
+	content, _ := os.ReadFile(filepath)
+	return strings.Split(string(content), "\n")
+}
+
+func PartOne(data []string) int {
+	instructions := make(map[string]string)
+	for _, line := range data {
+		if parts := strings.Split(line, " -> "); len(parts) == 2 {
+			instructions[parts[1]] = parts[0]
+		}
+	}
+
+	cache := make(map[string]uint16)
+	var evaluate func(string) uint16
+	evaluate = func(wire string) uint16 {
+		if value, ok := cache[wire]; ok {
+			return value
+		}
+		if num, err := strconv.Atoi(wire); err == nil {
+			return uint16(num)
+		}
+		expression, exists := instructions[wire]
+		if !exists {
+			return 0
+		}
+		parts := strings.Fields(expression)
+		var result uint16
+		switch {
+		case len(parts) == 1:
+			result = evaluate(parts[0])
+		case parts[0] == "NOT":
+			result = ^evaluate(parts[1])
+		default:
+			left, right := evaluate(parts[0]), evaluate(parts[2])
+			switch parts[1] {
+			case "AND":
+				result = left & right
+			case "OR":
+				result = left | right
+			case "LSHIFT":
+				result = left << right
+			case "RSHIFT":
+				result = left >> right
+			}
+		}
+		cache[wire] = result
+		return result
+	}
+	return int(evaluate("a"))
+}
+
+func PartTwo(data []string) int {
+	return 0
+}