Leetcode 345. Reverse Vowels of a String

Posted 2020-07-08 琴影

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1: Given s = "hello", return "holle".

Example 2: Given s = "leetcode", return "leotcede".

思路: 用一个hash表存一下元音字符, 然后设置左右指针找到两个都是元音的位置交换一下就可以了. 注意字符是大小写都有的.

 1 class Solution {
 2 public:
 3     string reverseVowels(string s) {
 4         set<char> hash{\'a\', \'e\', \'o\', \'i\', \'u\',\'A\', \'E\', \'I\', \'O\', \'U\'};
 5         int len = s.length();
 6         int left = 0, right = len - 1;
 7         while(left < right){
 8             if(hash.count(s[left]) == 0)
 9                 left++;
10             if(hash.count(s[right]) == 0)
11                 right--;
12             if(hash.count(s[left]) != 0 && hash.count(s[right]) != 0 ){
13                 swap(s[left], s[right]);
14                 left++;
15                 right--;
16             }
17         }
18         return s;
19         
20     }
21 };

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