409. Longest Palindrome-最长回文串

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.

Solution in python:

class Solution:
    def longestPalindrome(self, s: str) -> int:
        adic = dict()
        for item in s:
            if item not in adic:
                adic[item] = 1
            else:
                adic[item] += 1
        count, odd, flag = 0, 0, 0
        for key in adic.keys():
            if adic[key] % 2 == 0:
                count += adic[key]
            else:
                count += adic[key]-1
                flag = 1
        return count+flag