344. Reverse String (Rust)

Author: maxvoronov

rust/_0344_reverse_string/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "_0344_reverse_string"
+version = "0.1.0"
+edition = "2021"

rust/_0344_reverse_string/src/lib.rs

@@ -0,0 +1,42 @@
+pub fn reverse_string(s: &mut Vec<char>) {
+    if s.len() < 2 {
+        return;
+    }
+
+    let mut idx = 0;
+    loop {
+        let pair_idx = s.len() - idx - 1;
+        if pair_idx <= idx {
+            break;
+        }
+
+        let c = s[idx];
+        s[idx] = s[pair_idx];
+        s[pair_idx] = c;
+        idx += 1;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn reverse_string() {
+        struct Case {
+            input: Vec<char>,
+            want: Vec<char>,
+        }
+
+        let cases = vec![
+            Case { input: vec!['h', 'e', 'l', 'l', 'o'], want: vec!['o', 'l', 'l', 'e', 'h'] },
+            Case { input: vec!['H', 'a', 'n', 'n', 'a', 'h'], want: vec!['h', 'a', 'n', 'n', 'a', 'H'] },
+            Case { input: vec!['A'], want: vec!['A'] },
+            Case { input: vec![], want: vec![] },
+        ];
+
+        for case in cases.iter() {
+            let mut got = case.input.clone();
+            super::reverse_string(&mut got);
+            assert_eq!(case.want, got);
+        }
+    }
+}