day04

1 files changed, 145 insertions, 0 deletions

diff --git a/2024/day04.rs b/2024/day04.rs
new file mode 100644
index 0000000..f4dc88f
--- /dev/null
+++ b/2024/day04.rs
@@ -0,0 +1,145 @@
+#![allow(dead_code)]
+#![allow(unused_variables)]
+#![allow(unused_mut)]
+use std::env;
+use std::fs::File;
+use std::io::Read;
+
+fn horizontal(lx: usize, ly: usize, m: &Vec<Vec<char>>) -> usize {
+    let mut count = 0;
+    for y in 0..ly {
+        for x in 0..lx - 3 {
+            if m[y][x] == 'X' && m[y][x + 1] == 'M' && m[y][x + 2] == 'A' && m[y][x + 3] == 'S' {
+                count += 1;
+            }
+            if m[y][x] == 'S' && m[y][x + 1] == 'A' && m[y][x + 2] == 'M' && m[y][x + 3] == 'X' {
+                count += 1;
+            }
+        }
+    }
+    count
+}
+
+fn vertical(lx: usize, ly: usize, m: &Vec<Vec<char>>) -> usize {
+    let mut count = 0;
+    for y in 0..ly - 3 {
+        for x in 0..lx {
+            if m[y][x] == 'X' && m[y + 1][x] == 'M' && m[y + 2][x] == 'A' && m[y + 3][x] == 'S' {
+                count += 1;
+            }
+            if m[y][x] == 'S' && m[y + 1][x] == 'A' && m[y + 2][x] == 'M' && m[y + 3][x] == 'X' {
+                count += 1;
+            }
+        }
+    }
+    count
+}
+
+fn diag1(lx: usize, ly: usize, m: &Vec<Vec<char>>) -> usize {
+    let mut count = 0;
+    for y in 0..ly - 3 {
+        for x in 0..lx - 3 {
+            if m[y][x] == 'X'
+                && m[y + 1][x + 1] == 'M'
+                && m[y + 2][x + 2] == 'A'
+                && m[y + 3][x + 3] == 'S'
+            {
+                count += 1;
+            }
+            if m[y][x] == 'S'
+                && m[y + 1][x + 1] == 'A'
+                && m[y + 2][x + 2] == 'M'
+                && m[y + 3][x + 3] == 'X'
+            {
+                count += 1;
+            }
+        }
+    }
+    count
+}
+fn diag2(lx: usize, ly: usize, m: &Vec<Vec<char>>) -> usize {
+    let mut count = 0;
+    for y in 0..ly - 3 {
+        for x in 0..lx - 3 {
+            if m[y][x + 3] == 'X'
+                && m[y + 1][x + 2] == 'M'
+                && m[y + 2][x + 1] == 'A'
+                && m[y + 3][x] == 'S'
+            {
+                count += 1;
+            }
+            if m[y][x + 3] == 'S'
+                && m[y + 1][x + 2] == 'A'
+                && m[y + 2][x + 1] == 'M'
+                && m[y + 3][x] == 'X'
+            {
+                count += 1;
+            }
+        }
+    }
+    count
+}
+
+fn mas(lx: usize, ly: usize, m: &Vec<Vec<char>>) -> usize {
+    let mut count = 0;
+    for y in 1..ly - 1 {
+        for x in 1..lx - 1 {
+            if m[y][x] != 'A' {
+                continue;
+            }
+            let a = [
+                m[y - 1][x - 1],
+                m[y - 1][x + 1],
+                m[y + 1][x + 1],
+                m[y + 1][x - 1],
+            ];
+            if a == ['M', 'M', 'S', 'S']
+                || a == ['S', 'M', 'M', 'S']
+                || a == ['S', 'S', 'M', 'M']
+                || a == ['M', 'S', 'S', 'M']
+            {
+                count += 1;
+            }
+        }
+    }
+    count
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    let filename = if args.len() == 1 {
+        "in/".to_owned() + args[0].split('/').last().unwrap() + ".pzl"
+    } else {
+        args[1].clone()
+    };
+    let mut f = File::open(filename).expect("cannot open file");
+    let mut content = String::new();
+    f.read_to_string(&mut content).expect("cannot read file");
+    let lines = content.trim_end().split("\n");
+
+    let mut m: Vec<Vec<char>> = Vec::new();
+    for line in lines {
+        let mut l: Vec<char> = Vec::new();
+        for c in line.bytes() {
+            l.push(c as char)
+        }
+        m.push(l)
+    }
+    //println!("{:?}", m);
+
+    let ly = m.len();
+    let lx = m[0].len();
+
+    let mut res1 = 0;
+    res1 += horizontal(lx, ly, &m);
+    res1 += vertical(lx, ly, &m);
+    res1 += diag1(lx, ly, &m);
+    res1 += diag2(lx, ly, &m);
+
+    let res2 = mas(lx, ly, &m);
+
+    println!("res1: {}", res1);
+    println!("res2: {}", res2);
+    assert_eq!(res1, 2575);
+    assert_eq!(res2, 2041);
+}