Leetcode - 409. Longest Palindrome

https://leetcode.com/problems/longest-palindrome/submissions/

/**
 * @param {string} s
 * @return {number}
 */
var longestPalindrome = function (s) {
  let longest = 0;
  let keys = {};

  for (const char of s) {
    keys[char] = (keys[char] || 0) + 1;
    if (keys[char] % 2 === 0) {
      longest += 2;
    }
  }
  return s.length > longest ? longest + 1 : longest;
};

Runtime: 106 ms, faster than 58.34% of JavaScript online submissions for Longest Palindrome.

Memory Usage: 43.5 MB, less than 73.08% of JavaScript online submissions for Longest Palindrome.