add: Longest Palindrome

Author: sidvishnoi

0409-longest-palindrome.rs

@@ -0,0 +1,26 @@
+struct Solution;
+
+impl Solution {
+    pub fn longest_palindrome(s: String) -> i32 {
+        let mut counts = [0; 128];
+        for ch in s.into_bytes() {
+            counts[ch as usize] += 1;
+        }
+        let mut longest_palindrome_length = 0;
+        for count in counts.iter() {
+            longest_palindrome_length += (count / 2) * 2;
+            if longest_palindrome_length % 2 == 0 && count % 2 != 0 {
+                longest_palindrome_length += 1;
+            }
+        }
+        longest_palindrome_length
+    }
+}
+
+fn main() {
+    assert_eq!(7, Solution::longest_palindrome("abccccdd".to_string()));
+    assert_eq!(9, Solution::longest_palindrome("abccccddEE".to_string()));
+    assert_eq!(1, Solution::longest_palindrome("Aa".to_string()));
+    assert_eq!(2, Solution::longest_palindrome("bb".to_string()));
+    assert_eq!(1, Solution::longest_palindrome("zZ".to_string()));
+}