409. Longest Palindrome [Easy] 最

class Solution(object):
    def longestPalindrome(self, s):
        """
        :type s: str
        :rtype: int
        """
        mydic = {}
        for i in s:
            mydic[i] = mydic.get(i,0) + 1
        res = 0
        flag = False
        for i in mydic.values():
            if i % 2 == 0:
                res += i
            else:
                res += i-1
                flag = True
        return res+1 if flag else res