add day02 solution

2024/src/day02.rs

@@ -0,0 +1,66 @@
+use std::fs::read_to_string;
+
+fn check_report(report: &Vec<i32>) -> bool {
+    let desc = report[0] > report[1];
+    for x in report.windows(2) {
+        let prev = if desc { x[0] } else { x[1] };
+        let curr = if desc { x[1] } else { x[0] };
+        let dist = prev - curr;
+        if dist > 3 || dist < 1 || prev < curr {
+            return false;
+        }
+    }
+    true
+}
+
+pub fn stage1(input: &str) -> usize {
+    read_to_string(input)
+        .unwrap()
+        .lines()
+        .map(|line| {
+            line.split_whitespace()
+                .map(|x| x.parse::<i32>().unwrap())
+                .collect::<Vec<i32>>()
+        })
+        .filter(|report| check_report(report))
+        .count()
+}
+
+pub fn stage2(input: &str) -> usize {
+    read_to_string(input)
+        .unwrap()
+        .lines()
+        .map(|line| {
+            line.split_whitespace()
+                .map(|x| x.parse::<i32>().unwrap())
+                .collect::<Vec<_>>()
+        })
+        .filter(|report| {
+            for y in 0..report.len() {
+                let mut variant = report.clone();
+                variant.remove(y);
+                if check_report(&variant) {
+                    return true;
+                }
+            }
+            false
+        })
+        .count()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_stage1() {
+        assert_eq!(stage1("input/02_input.example"), 2);
+        assert_eq!(stage1("input/02_input.txt"), 463);
+    }
+
+    #[test]
+    fn test_stage2() {
+        assert_eq!(stage2("input/02_input.example"), 4);
+        assert_eq!(stage2("input/02_input.txt"), 514);
+    }
+}

2024/src/lib.rs

@@ -1,2 +1,3 @@
 #[allow(dead_code)]
 mod day01;
+mod day02;