2025 days 1-4

2025/01/dy-tea.v

@@ -0,0 +1,50 @@
+import os
+import math
+
+// part 1
+lines := os.read_lines('rotations.input')!
+mut dial := 50
+mut count := 0
+for line in lines {
+	dir := line[0]
+	turns := line[1..].int()
+	dial += turns * if dir == `L` { -1 } else { 1 }
+	for dial > 99 {
+		dial -= 100
+	}
+	for dial < 0 {
+		dial += 100
+	}
+	if dial == 0 {
+		count++
+	}
+}
+println(count)
+
+// part 2
+dial = 50
+count = 0
+for line in lines {
+	dir := line[0]
+	turns := line[1..].int()
+	delta := turns * if dir == `L` { -1 } else { 1 }
+	dial += delta
+	if delta < 0 {
+		if dial >= 0 {
+			if dial == 0 {
+				count++
+			}
+			continue
+		}
+		if dial - delta != 0 {
+			count++
+		}
+		dial = math.abs(dial)
+		count += dial / 100
+		dial = (100 - dial % 100) % 100
+	} else {
+		count += dial / 100
+		dial %= 100
+	}
+}
+println(count)

2025/01/rotations.input

@@ -0,0 +1,10 @@
+L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82

2025/02/dy-tea.v

@@ -0,0 +1,41 @@
+import os
+
+line := os.read_lines('ids.input')![0]
+items := line.split(',')
+
+// part 1
+mut sum := u64(0)
+for item in items {
+	left, right := item.split_once('-') or { panic('invalid input') }
+	start := left.u64()
+	end := right.u64()
+	for i in start .. end + 1 {
+		s := i.str()
+		if s.len % 2 == 0 {
+			if s[0..s.len / 2] == s[s.len / 2..s.len] {
+				sum += i
+			}
+		}
+	}
+}
+println(sum)
+
+// part 2
+sum = 0
+for item in items {
+	left, right := item.split_once('-') or { panic('invalid input') }
+	start := left.u64()
+	end := right.u64()
+	for i in start .. end + 1 {
+		s := i.str()
+		for x in 1 .. s.len / 2 + 1 {
+			if s.len % x == 0 {
+				if s[0..x].repeat(s.len / x) == s {
+					sum += i
+					break
+				}
+			}
+		}
+	}
+}
+println(sum)

2025/02/ids.input

@@ -0,0 +1 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124

2025/03/banks.input

@@ -0,0 +1,4 @@
+987654321111111
+811111111111119
+234234234234278
+818181911112111

2025/03/dy-tea.v

@@ -0,0 +1,45 @@
+import os
+
+lines := os.read_lines('banks.input')!
+
+// part 1
+mut sum := u64(0)
+for line in lines {
+	mut max := 0
+	l := line.runes()
+	for i, x in l {
+		for y in l[i + 1..] {
+			dig := '${x}${y}'.int()
+			if dig > max {
+				max = dig
+			}
+		}
+	}
+	sum += u64(max)
+}
+println(sum)
+
+// part 2
+sum = 0
+for line in lines {
+	mut max := u64(0)
+	mut prev := 0
+	l := line.runes()
+	for i in 0 .. 12 {
+		mut dig := 0
+		for j in prev .. (l.len - 11 + i) {
+			c := l[j].str().int()
+			if dig >= c {
+				continue
+			}
+			dig = c
+			prev = j + 1
+			if dig == 9 {
+				break
+			}
+		}
+		max = max * u64(10) + u64(dig)
+	}
+	sum += max
+}
+println(sum)

2025/04/department.input

@@ -0,0 +1,10 @@
+..@@.@@@@.
+@@@.@.@.@@
+@@@@@.@.@@
+@.@@@@..@.
+@@.@@@@.@@
+.@@@@@@@.@
+.@.@.@.@@@
+@.@@@.@@@@
+.@@@@@@@@.
+@.@.@@@.@.

2025/04/dy-tea.v

@@ -0,0 +1,64 @@
+import os
+
+lines := os.read_lines('department.input')!
+offsets := [[-1, -1], [0, -1], [-1, 0], [1, 1], [1, 0], [0, 1],
+	[1, -1], [-1, 1]]
+
+// part 1
+mut sum := 0
+for x, line in lines {
+	iter: for y, ch in line {
+		if ch == `.` {
+			continue
+		}
+		mut count := 0
+		for pos in offsets {
+			nx := x + pos[0]
+			ny := y + pos[1]
+			if nx < 0 || nx >= line.len || ny < 0 || ny >= lines.len {
+				continue
+			}
+			if lines[nx][ny] == `@` {
+				count++
+			}
+			if count > 3 {
+				continue iter
+			}
+		}
+		sum++
+	}
+}
+println(sum)
+
+// part 2
+sum = 0
+mut grid := lines.map(|l| l.runes())
+mut removed := 1
+for removed != 0 {
+	removed = 0
+	for x, row in grid {
+		loop: for y, ch in row {
+			if ch == `.` {
+				continue
+			}
+			mut count := 0
+			for pos in offsets {
+				nx := x + pos[0]
+				ny := y + pos[1]
+				if nx < 0 || nx >= row.len || ny < 0 || ny >= grid.len {
+					continue
+				}
+				if grid[nx][ny] == `@` {
+					count++
+				}
+				if count > 3 {
+					continue loop
+				}
+			}
+			grid[x][y] = `.`
+			removed++
+			sum++
+		}
+	}
+}
+println(sum)

known/2025/01/dy-tea.out

@@ -0,0 +1,2 @@
+3
+6

known/2025/02/dy-tea.out

@@ -0,0 +1,2 @@
+1227775554
+4174379265

known/2025/03/dy-tea.out

@@ -0,0 +1,2 @@
+357
+3121910778619

known/2025/04/dy-tea.out

@@ -0,0 +1,2 @@
+13
+43