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+...O...O.......#............O#O#..#.O....O#..OOO.#O#..OO.O...........OO...#...OOOO...#..O##O.O..#...
+.O.O....O.#O.O#...#.#...........#.O.O#.#..O.#........O..O...#....O........O..O.#.#.#...#.........#O.
+.O#..#O...#.O#.#...#...O...#..O##O..O......O.O....#O.#..O#OOO.O.#.........O....O.#.O....#OO....#...O
+O#...#....#.#...#...O..##.#.....O.#..#.O....###O..O.OO#.....O...O.......#.....#O......#...OO.#.O..#.
+O.O#O.#...OO##.#OO..#...O..OO#.O.....##..OO.....##..#O...#...OO#.O...#......#.O#..##..#.O.....O#.#.O
+O..#O.O...OO.#O.O....#.OO...O...#..O.O..#OO............#........O..#.....#OOOO...O......O.##.O....O#
+#...#OO.OO.#.#...O...O....O..##.O...#..O.......####.....#......#..O...#.##....#O..O..O.#.#.#......O.
+.....O...O..#.O#...O..#.#.O#.O.OO.#..........O...OO#O#.....#.OO.........#OO.O...O..OO.O.#......O##..
diff --git a/2023/day14/src/main.rs b/2023/day14/src/main.rs
new file mode 100644
index 0000000..c5b15fb
--- /dev/null
+++ b/2023/day14/src/main.rs
@@ -0,0 +1,138 @@
+// Problem: https://adventofcode.com/2023/day/14
+
+use std::collections::HashMap;
+
+type Result = usize;
+
+type Input = Vec<Vec<char>>;
+
+fn parse_input(input: &str) -> Input {
+    input
+        .trim()
+        .lines()
+        .map(|line| line.chars().collect())
+        .collect()
+}
+
+// ------------------------------------------
+
+fn part1(input: &Input) -> Result {
+    let l = input.len();
+    let mut prev = input.clone();
+    loop {
+        let mut input = prev.clone();
+        for r in (1..l).rev() {
+            for c in 0..input[0].len() {
+                let mut up = 0;
+                while up < r && input[r - up][c] == 'O' && input[r - up - 1][c] == '.' {
+                    input[r][c] = '.';
+                    input[r - 1][c] = 'O';
+                    up += 1;
+                }
+            }
+        }
+        if prev == input {
+            break;
+        }
+        prev = input;
+    }
+    let input = prev;
+
+    let mut res = 0;
+    for (i, line) in input.iter().enumerate() {
+        res += line.iter().filter(|c| **c == 'O').count() * (l - i)
+    }
+    res
+}
+
+#[test]
+fn test_part1() {
+    let input = parse_input(include_str!("test.txt"));
+    assert_eq!(part1(&input), 136);
+}
+
+// ------------------------------------------
+
+fn tilt(input: &Vec<Vec<char>>) -> Vec<Vec<char>> {
+    let mut prev = input.clone();
+    let l = input.len();
+    loop {
+        let mut input = prev.clone();
+        for r in (1..l).rev() {
+            for c in 0..input[0].len() {
+                let mut up = 0;
+                while up < r && input[r - up][c] == 'O' && input[r - up - 1][c] == '.' {
+                    input[r][c] = '.';
+                    input[r - 1][c] = 'O';
+                    up += 1;
+                }
+            }
+        }
+        if prev == input {
+            break;
+        }
+        prev = input;
+    }
+    prev
+}
+
+fn rotate(v: Vec<Vec<char>>) -> Vec<Vec<char>> {
+    assert!(!v.is_empty());
+    let len = v[0].len();
+    let mut iters: Vec<_> = v.into_iter().map(|n| n.into_iter()).collect();
+    (0..len)
+        .map(|_| {
+            iters
+                .iter_mut()
+                .map(|n| n.next().unwrap())
+                .rev()
+                .collect::<Vec<char>>()
+        })
+        .collect()
+}
+
+fn part2(input: &Input) -> Result {
+    let mut seen = HashMap::new();
+    let mut prev = input.clone();
+    let mut i = 0;
+    let mut s = true;
+    while i < 1000000000 {
+        let mut cur = prev.clone();
+        for _ in 0..4 {
+            cur = tilt(&cur);
+            cur = rotate(cur);
+        }
+        if s {
+            if let Some(idx) = seen.get(&cur) {
+                let cycle_size = i - idx;
+                let remaining = 1000000000 - i;
+                i += cycle_size * (remaining / cycle_size);
+                s = false;
+            } else {
+                seen.insert(cur.clone(), i);
+            }
+        }
+        prev = cur;
+        i += 1;
+    }
+
+    let mut res = 0;
+    for (i, line) in prev.iter().enumerate() {
+        res += line.iter().filter(|c| **c == 'O').count() * (input.len() - i)
+    }
+    res
+}
+
+#[test]
+fn test_part2() {
+    let input = parse_input(include_str!("test.txt"));
+    assert_eq!(part2(&input), 64);
+}
+
+// ------------------------------------------
+
+fn main() {
+    let input = parse_input(include_str!("input.txt"));
+    println!("Part 1: {:?}", part1(&input));
+    println!("Part 2: {:?}", part2(&input));
+}
diff --git a/2023/day14/src/test.txt b/2023/day14/src/test.txt
new file mode 100644
index 0000000..5a24dce
--- /dev/null
+++ b/2023/day14/src/test.txt
@@ -0,0 +1,10 @@
+O....#....
+O.OO#....#
+.....##...
+OO.#O....O
+.O.....O#.
+O.#..O.#.#
+..O..#O..O
+.......O..
+#....###..
+#OO..#....