Problem

Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: “Let’s take LeetCode contest”

Output: “s’teL ekat edoCteeL tsetnoc”

Note: In the string, each word is separated by single space and there will not be any extra space in the string.

Pre analysis

Will split/join each word

Another solution

var reverseWords = function(s) {
    let res = '';
    let stack = '';

    for (let i = 0; i <= s.length; i++) {
        const char = s[i];

        if (char === ' ') {
            res += stack + ' ';
            stack = '';
        } else if (!char) {
            res += stack;
        } else {
            stack = char + stack;
        }
    }

    return res;
};