iT邦幫忙

2021 iThome 鐵人賽

DAY 8
0
自我挑戰組

開學之前....系列 第 11

Day12 - 409. Longest Palindrome

今日題目:409. Longest Palindrome

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

解題技巧

1. str.count(sub, start= 0,end=len(string))

str = 'banana pie banana'
str.count('a',2)
->5

2. collections.Counter()

str2 = 'gallahad'

  • c = Counter(str2)
    ->Counter({'a': 3, 'n': 2, 'b': 1, 's': 1})

  • Counter.items()->['a': 3, 'n': 2, 'b': 1, 's': 1]

  • Counter.values()->[3,2,1,1]

  • Counter.keys()->['a','n','b','s']

My solution

class Solution:
    def longestPalindrome(self, s: str) -> int:
        n = len(s)
        c = collections.Counter(s)
    
        ans = 0
        odd = 0
        
        for v in c.values():
            ans += int(v/2)*2

            if ans%2 ==0 and v%2==1:
                ans +=1
        return ans

Result

https://ithelp.ithome.com.tw/upload/images/20210927/20140843wb7Emx2ypf.png


上一篇
Day11-415. Add Strings
下一篇
Day13-290. Word Pattern
系列文
開學之前....20

尚未有邦友留言

立即登入留言