public class Solution
extends Object
409 - Longest Palindrome\.
Easy
Given a string `s` which consists of lowercase or uppercase letters, return _the length of the **longest palindrome**_ that can be built with those letters.
Letters are **case sensitive** , for example, `"Aa"` is not considered a palindrome here.
**Example 1:**
**Input:** s = "abccccdd"
**Output:** 7
**Explanation:** One longest palindrome that can be built is "dccaccd", whose length is 7.
**Example 2:**
**Input:** s = "a"
**Output:** 1
**Example 3:**
**Input:** s = "bb"
**Output:** 2
**Constraints:**
* `1 <= s.length <= 2000`
* `s` consists of lowercase **and/or** uppercase English letters only.