leetcode-345-Reverse-Vowels-of-a-String

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描述

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”.

分析

建立一个元音的哈希表，一前一后两指针向中间推进，每推进一次交换一次。

解决方案1(C++)

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class Solution {
public:
    string reverseVowels(string s) {
        bool hash_table[128] = {false};
        hash_table['a'] = true, hash_table['e'] = true, hash_table['i'] = true, hash_table['o'] = true, hash_table['u'] = true;
        hash_table['A'] = true, hash_table['E'] = true, hash_table['I'] = true, hash_table['O'] = true, hash_table['U'] = true;
        int len = s.size();
        int left = 0;
        int right = len - 1;
        string res = s;
        
        if(len < 2) {
            return res;
        }
        
        while(left < right) {
            while(!hash_table[res[left]]) {
                left++;
            }
            while(!hash_table[res[right]]) {
                right--;
            }
            if(left < right) {
                swap(res[left], res[right]);
            }
            left++;
            right--;
        }
        return res;
    }
};

相关问题

(E) Reverse String

题目来源