Second task

02/02.rs

@@ -0,0 +1,35 @@
+use std::fs;
+
+fn main() {
+    let contents = fs::read_to_string("input").unwrap();
+    let mut count1 = 0;
+    let mut count2 = 0;
+    for line in contents.lines() {
+        let v: Vec<_> = line.split(':').collect();
+        let rule = v[0].split(' ').collect::<Vec<_>>();
+        let numbers = rule[0].split('-').collect::<Vec<_>>();
+        let (start, end) = (
+            numbers[0].parse::<usize>().unwrap(),
+            numbers[1].parse::<usize>().unwrap(),
+        );
+        let c = rule[1];
+        let password = &v[1][1..];
+        // Part 1
+        let char_count = password.matches(c).count();
+        if start <= char_count && char_count <= end {
+            count1 += 1;
+        }
+        // Part 2
+        let (start, end) = (start - 1, end - 1);
+        if password[start..start + 1] == *c {
+            if password[end..end + 1] != *c {
+                count2 += 1;
+            }
+        } else {
+            if password[end..end + 1] == *c {
+                count2 += 1;
+            }
+        }
+    }
+    println!("{} {}", count1, count2);
+}