345.reverse-vowels-of-a-string

描述

Given a string s, reverse only all the vowels in the string and return it.

The vowels are ‘a’, ‘e’, ‘i’, ‘o’, and ‘u’, and they can appear in both cases.

测试用例

Input: s = "leetcode"
Output: "leotcede"

题解

使用首尾指针循环，并交换对应的元音字母。

var reverseVowels = function (s) {
  // 列举元音字母
  let vowels = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"];
  let l = s.length， i = 0, j = l - i - 1;
  // & js字符串字符不能直接赋值，强制转换成数组
  s = s.split('');
  while (i < j) {
    // 当前字母是否为元音字母
    let is_i = vowels.indexOf(s[i]) > -1,
      is_j = vowels.indexOf(s[j]) > -1;
    if (is_i && is_j) {
      let temp = s[j];
      s[j] = s[i];
      s[i] = temp;
      i++, j--;
    } else if (!is_i) {
      i++;
    } else if (!is_j) {
      j--;
    }
  }
  return s.join('');
};

结果

Accepted

480/480 cases passed (104 ms)

Your runtime beats 47.29 % of javascript submissions

Your memory usage beats 51.31 % of javascript submissions (45.3 MB)