Day 7

d07/main.odin

@@ -0,0 +1,90 @@
+package main
+
+import "core:container/queue"
+import "core:fmt"
+import "core:math"
+import "core:math/linalg"
+import "core:os"
+import "core:slice"
+import "core:strconv"
+import "core:strings"
+import "core:time"
+import "core:unicode/utf8"
+
+import util "../util"
+
+Vec2 :: [2]int
+
+count_paths :: proc(pos: Vec2, lines: []string, cache: ^map[Vec2]i64) -> i64 {
+	if pos.y >= len(lines) do return 1
+
+	if cached, ok := cache[pos]; ok do return cached
+
+	result: i64 = 0
+	switch lines[pos.y][pos.x] {
+	case '^':
+		result =
+			count_paths(Vec2{pos.x - 1, pos.y + 1}, lines, cache) +
+			count_paths(Vec2{pos.x + 1, pos.y + 1}, lines, cache)
+	case:
+		result = count_paths(Vec2{pos.x, pos.y + 1}, lines, cache)
+	}
+	cache[pos] = result
+
+	return result
+}
+
+part_1 :: proc(lines: []string) {
+	result: i64 = 0
+	start_x, _ := slice.linear_search(transmute([]u8)lines[0], 'S')
+
+	stack := make([dynamic]Vec2)
+	visited := make(map[Vec2]struct{})
+	append(&stack, Vec2{start_x, 0})
+
+	for len(stack) > 0 {
+		pos := pop(&stack)
+		if pos.y >= len(lines) do continue
+		if pos in visited do continue
+		visited[pos] = {}
+
+		switch lines[pos.y][pos.x] {
+		case '^':
+			append(&stack, Vec2{pos.x - 1, pos.y + 1})
+			append(&stack, Vec2{pos.x + 1, pos.y + 1})
+			result += 1
+		case:
+			append(&stack, Vec2{pos.x, pos.y + 1})
+		}
+	}
+
+	fmt.printfln("  [Result] %v", result)
+}
+
+part_2 :: proc(lines: []string) {
+	cache := make(map[Vec2]i64)
+	start_x, _ := slice.linear_search(transmute([]u8)lines[0], 'S')
+	result := count_paths(Vec2{start_x, 0}, lines, &cache)
+	fmt.printfln("  [Result] %v", result)
+}
+
+main :: proc() {
+	context.allocator = context.temp_allocator
+	defer free_all(context.temp_allocator)
+
+	INPUT :: #load("input.txt", string)
+	lines := strings.split(INPUT, "\n")
+	lines = lines[:len(lines) - 1]
+
+	fmt.println("[Part 1]")
+	start := time.tick_now()
+	part_1(lines)
+	duration := time.tick_diff(start, time.tick_now())
+	fmt.printfln("  [Time]   %vms\n", time.duration_milliseconds(duration))
+
+	fmt.printfln("[Part 2]")
+	start = time.tick_now()
+	part_2(lines)
+	duration = time.tick_diff(start, time.tick_now())
+	fmt.printfln("  [Time]   %vms", time.duration_milliseconds(duration))
+}