add solutions for day 18 and 19

2024/18/dy-tea.v

@@ -0,0 +1,96 @@
+import os
+import math
+import strconv
+
+const input_file = 'positions.input'
+
+fn print_grid(grid [][]bool) {
+	for i in 0 .. grid.len {
+		for j in 0 .. grid[i].len {
+			print(if grid[i][j] { '#' } else { '.' })
+		}
+		print('\n')
+	}
+}
+
+fn solve_maze(grid [][]bool, sx int, sy int, ex int, ey int) int {
+	dirs := [[1, 0], [0, -1], [-1, 0], [0, 1]]
+	mut queue := [][]int{}
+	mut visited := map[string]int{}
+	mut min := max_int
+
+	queue << [sx, sy, 0]
+	visited['${sx},${sy}'] = 0
+
+	for queue.len > 0 {
+		curr := queue[0]
+
+		cx := curr[0]
+		cy := curr[1]
+		cc := curr[2]
+
+		queue.delete(0)
+
+		if cx == ex && cy == ey {
+			min = math.min(min, cc)
+			continue
+		}
+
+		for i in 0 .. 4 {
+			nx, ny := cx + dirs[i][0], cy + dirs[i][1]
+			if nx >= 0 && ny >= 0 && ny < grid.len && nx < grid[0].len && !grid[nx][ny] {
+				key := '${nx},${ny}'
+				nc := cc + 1
+				if key !in visited || visited[key] > nc {
+					visited[key] = nc
+					queue << [nx, ny, nc]
+				}
+			}
+		}
+	}
+
+	return min
+}
+
+fn p1(input string) ! {
+	lines := os.read_lines(input)!
+
+	mut grid := [][]bool{len: 71, init: []bool{len: 71, init: false}}
+
+	for i, line in lines {
+		x, y := line.split_once(',') or { '', '' }
+
+		if i == 1024 {
+			break
+		}
+
+		grid[strconv.atoi(x)!][strconv.atoi(y)!] = true
+	}
+
+	println(solve_maze(grid, 0, 0, 70, 70))
+}
+
+fn p2(input string) ! {
+	lines := os.read_lines(input)!
+
+	mut grid := [][]bool{len: 71, init: []bool{len: 71, init: false}}
+
+	for line in lines {
+		x, y := line.split_once(',') or { '', '' }
+
+		grid[strconv.atoi(x)!][strconv.atoi(y)!] = true
+
+		if solve_maze(grid, 0, 0, 70, 70) == max_int {
+			print_grid(grid)
+			println(line)
+			break
+		}
+	}
+}
+
+fn main() {
+	p1(input_file)!
+
+	// Note that the example input does not block off the exit and therefore does not have an answer
+	p2(input_file)!
+}

2024/18/positions.input

@@ -0,0 +1,25 @@
+5,4
+4,2
+4,5
+3,0
+2,1
+6,3
+2,4
+1,5
+0,6
+3,3
+2,6
+5,1
+1,2
+5,5
+2,5
+6,5
+1,4
+0,4
+6,4
+1,1
+6,1
+1,0
+0,5
+1,6
+2,0

2024/19/dy-tea.v

@@ -0,0 +1,97 @@
+import os
+
+const input_file := 'towels.input'
+
+fn possible(towels []string, current string, query string, mut visited map[string]bool) bool {
+	if current == query {
+		return true
+	}
+
+	if current.len >= query.len {
+		return false
+	}
+
+	if visited[current] {
+		return false
+	}
+
+	visited[current] = true
+
+	for towel in towels {
+		n := current + towel
+
+		if query == n {
+			return true
+		}
+
+		if query.starts_with(n) {
+			if possible(towels, n, query, mut visited) {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+fn count_combinations(towels []string, current string, query string, mut visited map[string]u64) u64 {
+	if current == query {
+		return 1
+	}
+
+	if current.len >= query.len {
+		return 0
+	}
+
+	if current in visited {
+		return visited[current]
+	}
+
+	mut sum := u64(0)
+
+	for towel in towels {
+		n := current + towel
+
+		if query.starts_with(n) {
+			sum += count_combinations(towels, n, query, mut visited)
+		}
+	}
+
+	visited[current] = sum
+	return sum
+}
+
+fn p1(input string) ! {
+	lines := os.read_lines(input)!
+
+	towels := lines[0].split(', ')
+	queries := lines[2..]
+
+	mut sum := 0
+	for query in queries {
+		mut visited := map[string]bool{}
+		sum += if possible(towels, '', query, mut visited) { 1 } else { 0 }
+	}
+
+	println(sum)
+}
+
+fn p2(input string) ! {
+	lines := os.read_lines(input)!
+
+	towels := lines[0].split(', ')
+	queries := lines[2..]
+
+	mut sum := u64(0)
+	for query in queries {
+		mut visited := map[string]u64{}
+		sum += count_combinations(towels, '', query, mut visited)
+	}
+
+	println(sum)
+}
+
+fn main() {
+	p1(input_file)!
+	p2(input_file)!
+}

2024/19/towels.input

@@ -0,0 +1,10 @@
+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb

known/2024/18/dy-tea.out

@@ -0,0 +1 @@
+146

known/2024/19/dy-tea.out

@@ -0,0 +1,2 @@
+6
+16