leetcode 1704. Determine if String Halves Are Alike（python）

描述

You are given a string s of even length. Split this string into two halves of equal lengths, and let a be the first half and b be the second half.

Two strings are alike if they have the same number of vowels (‘a’, ‘e’, ‘i’, ‘o’, ‘u’, ‘A’, ‘E’, ‘I’, ‘O’, ‘U’). Notice that s contains uppercase and lowercase letters.

Return true if a and b are alike. Otherwise, return false.

Example 1:

Input: s = "book"
Output: true
Explanation: a = "bo" and b = "ok". a has 1 vowel and b has 1 vowel. Therefore, they are alike.	

Example 2:

Input: s = "textbook"
Output: false
Explanation: a = "text" and b = "book". a has 1 vowel whereas b has 2. Therefore, they are not alike.
Notice that the vowel o is counted twice.

Example 3:

Input: s = "MerryChristmas"
Output: false

Example 4:

Input: s = "AbCdEfGh"
Output: true

Note:

2 <= s.length <= 1000
s.length is even.
s consists of uppercase and lowercase letters.

解析

根据题意，只需要对前一半字符串和后一般字符串进行遍历，然后对出现的元音进行计数，最后比较两者的元音字符数量即可。

解答

class Solution(object):
    def halvesAreAlike(self, s):
        """
        :type s: str
        :rtype: bool
        """
        v = {'a':1, 'e':1, 'i':1, 'o':1, 'u':1, 'A':1, 'E':1, 'I':1, 'O':1, 'U':1}
        i = 0
        a, b=0, 0
        for i in range(len(s)//2):
            if s[i] in v:
                a+=1
            if s[-i-1] in v:
                b+=1
        return a==b

运行结果

Runtime: 16 ms, faster than 98.34% of Python online submissions for Determine if String Halves Are Alike.
Memory Usage: 13.4 MB, less than 70.36% of Python online submissions for Determine if String Halves Are Alike.

原题链接：https://leetcode.com/problems/determine-if-string-halves-are-alike/

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