Leetcode 151 - Reverse words in a string

Note:

  • Know how to use trim to remove leading or trailing spaces.
  • Use replace and / +/g regex to replace multi spaces with single space.
  • Convert string to arr, then use double pointers method to reverse.

Question:
Given an input string s, reverse the order of the words.

A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.

Return a string of the words in reverse order concatenated by a single space.

Note that s may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces.

Example:

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Input: s = "a good   example"
Output: "example good a"
Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.

Input: s = " hello world "
Output: "world hello"
Explanation: Your reversed string should not contain leading or trailing spaces.

Code:

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/**
* @param {string} s
* @return {string}
*/
var reverseWords = function(s) {
s = s.trim();
const regex = / +/g;
s = s.replace(regex, ' ');
const arr = s.split(' ');
let left = 0;
let right = arr.length - 1;
console.log(arr)
while (left < right) {
if (arr[left] === '') left++;
if (arr[right] === '') right--;
[arr[left++], arr[right--]] = [arr[right], arr[left]];
}
return arr.join(' ');
};