Day 15 part 1

Cargo.toml

@@ -22,3 +22,8 @@ path = "day14/part1.rs"
 [[bin]]
 name = "d14p2"
 path = "day14/part2.rs"
+
+[[bin]]
+name = "d15p1"
+path = "day15/part1.rs"
+

day15/part1.rs

@@ -0,0 +1,153 @@
+#![feature(const_str_split_at)]
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum BlockType {
+    Wall,
+    Box,
+    Empty,
+    Robot
+}
+
+#[derive(Debug, Clone, Copy)]
+enum InstructionType {
+    Up,
+    Down,
+    Left,
+    Right
+}
+
+const GRID_SIZE: usize = 50;
+const INSTRUCTIONS_LENGTH: usize = 1000;
+const INSTRUCTIONS_COUNT: usize = 20;
+
+const INPUT: (([[BlockType; GRID_SIZE]; GRID_SIZE], (usize, usize)), [InstructionType; INSTRUCTIONS_COUNT * INSTRUCTIONS_LENGTH]) = {
+    let split = include_str!("input.txt").split_at(GRID_SIZE * (GRID_SIZE + 1));
+    let grid_str = split.0.trim_ascii().as_bytes();
+
+    let mut grid = [[BlockType::Empty; GRID_SIZE]; GRID_SIZE];
+    let mut i = 0;
+    let mut newlines = 0;
+    let mut robot_pos = (0usize, 0usize);
+    while i < grid_str.len() {
+        if grid_str[i] == b'\n' {
+            newlines += 1;
+            i += 1;
+            continue;
+        };
+        
+        let row = (i - newlines) / GRID_SIZE;
+        let col = i - newlines - (row * GRID_SIZE);
+        grid[row][col] = match grid_str[i] {
+            b'#' => BlockType::Wall,
+            b'O' => BlockType::Box,
+            b'.' => BlockType::Empty,
+            b'@' => {
+                robot_pos = (row, col);
+                BlockType::Robot
+            },
+            _ => {
+                let mut tmp = [0u8; 4];
+                let your_string = (grid_str[i] as char).encode_utf8(&mut tmp);
+                panic!("{}", your_string);
+            }
+        };
+
+        i += 1;
+    }
+
+    let instructions_str = split.1.trim_ascii().as_bytes();
+    let mut i = 0;
+    let mut newlines = 0;
+    let mut instructions = [InstructionType::Up; INSTRUCTIONS_COUNT * INSTRUCTIONS_LENGTH];
+    while i < instructions_str.len() {
+        if instructions_str[i] == b'\n' {
+            newlines += 1;
+            i += 1;
+            continue;
+        }
+
+        instructions[i - newlines] = match instructions_str[i] {
+            b'^' => InstructionType::Up,
+            b'v' => InstructionType::Down,
+            b'<' => InstructionType::Left,
+            b'>' => InstructionType::Right,
+            _ => {
+                let mut tmp = [0u8; 4];
+                let your_string = (grid_str[i] as char).encode_utf8(&mut tmp);
+                panic!("{}", your_string);
+            }
+        };
+
+        i += 1;
+    }
+
+    ((grid, robot_pos), instructions)
+};
+
+fn main() {
+    let ((mut grid, mut robot_pos), instructions) = INPUT;
+
+    for instruction in instructions {
+        let mut next = match instruction {
+            InstructionType::Up => (robot_pos.0 - 1, robot_pos.1),
+            InstructionType::Down => (robot_pos.0 + 1, robot_pos.1),
+            InstructionType::Left => (robot_pos.0, robot_pos.1 - 1),
+            InstructionType::Right => (robot_pos.0, robot_pos.1 + 1)
+        };
+        
+        match grid[next.0][next.1] {
+            // Can't do anything if next is a wall
+            BlockType::Wall => continue,
+            // If empty, shrimply move there
+            BlockType::Empty => {
+                grid[robot_pos.0][robot_pos.1] = BlockType::Empty;
+                grid[next.0][next.1] = BlockType::Robot;
+                robot_pos = next;
+            },
+            // Wtf
+            BlockType::Robot => unreachable!(),
+            // Do box pusher logic
+            BlockType::Box => {
+                let original_box = next;
+                // Loop until we find a place to put the box
+                let mut failed = false;
+                loop {
+                    next = match instruction {
+                        InstructionType::Up => (next.0 - 1, next.1),
+                        InstructionType::Down => (next.0 + 1, next.1),
+                        InstructionType::Left => (next.0, next.1 - 1),
+                        InstructionType::Right => (next.0, next.1 + 1)
+                    };
+                    // Overflow impossible, breaks on wall
+                    match grid[next.0][next.1] {
+                        BlockType::Wall => {
+                            failed = true;
+                            break;
+                        },
+                        BlockType::Box => continue,
+                        BlockType::Empty => break,
+                        BlockType::Robot => unreachable!(),
+                    }
+                }
+                if !failed {
+                    // Move robot to box location
+                    grid[original_box.0][original_box.1] = BlockType::Robot;
+                    grid[robot_pos.0][robot_pos.1] = BlockType::Empty;
+                    robot_pos = original_box;
+                    // Put box in empty slot
+                    grid[next.0][next.1] = BlockType::Box;
+                }
+            },
+        }
+    }
+
+    let mut sum = 0_usize;
+    for row in 0..GRID_SIZE {
+        for col in 0..GRID_SIZE {
+            if grid[row][col] != BlockType::Box { continue }
+            sum += 100 * row + col;
+        }
+    }
+
+    println!("Result: {sum}")
+}

flake.lock

@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1733759999,
-        "narHash": "sha256-463SNPWmz46iLzJKRzO3Q2b0Aurff3U1n0nYItxq7jU=",
+        "lastModified": 1734119587,
+        "narHash": "sha256-AKU6qqskl0yf2+JdRdD0cfxX4b9x3KKV5RqA6wijmPM=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "a73246e2eef4c6ed172979932bc80e1404ba2d56",
+        "rev": "3566ab7246670a43abd2ffa913cc62dad9cdf7d5",
         "type": "github"
       },
       "original": {
@@ -62,11 +62,11 @@
         "nixpkgs": "nixpkgs_2"
       },
       "locked": {
-        "lastModified": 1733884434,
-        "narHash": "sha256-8GXR9kC07dyOIshAyfZhG11xfvBRSZzYghnZ2weOKJU=",
+        "lastModified": 1734402816,
+        "narHash": "sha256-cgQ8mjUJz7J3fp97lnvl0dSJ6vLt8yzUSmw3B7QKw94=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "d0483df44ddf0fd1985f564abccbe568e020ddf2",
+        "rev": "e38fbd6e56e8cd1d61c65a21bbb7785e966707b4",
         "type": "github"
       },
       "original": {

flake.nix

@@ -19,6 +19,7 @@
                         extensions = [ "rust-src" "rustfmt" ];
                         targets = [ "x86_64-unknown-linux-gnu" ];
                     }))
+                    evcxr
                 ];
             };
         });