lc409. Longest Palindrome

409. Longest Palindrome

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Share Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those letters.

This is case sensitive, for example "Aa" is not considered a palindrome here.

Note: Assume the length of given string will not exceed 1,010.

Example:

Input: "abccccdd"

Output: 7

Explanation: One longest palindrome that can be built is "dccaccd", whose length is 7.

思路：統計字符串中每一個字母的個數num，計數器count+=num/2,若是個數num有單數，最後組成的迴文長度爲count2+1，若是是複數，最後組成迴文長度爲count2

代碼：python3

class Solution:
	def longestPalindrome(self, s):
		counter = collections.Counter(s)
		count=0
		hasSingle=False
		for v in counter.values():
			if v%2==1:
				hasSingle=True
			count+=int(v/2)
		return count*2+1 if hasSingle else count*2
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