Anjan Dutta

Leet Code 557: Reverse Words in a String III

Problem statement:

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

Constraints:

1 <= s.length <= 5 * 104
s contains printable ASCII characters.
s does not contain any leading or trailing spaces.
There is at least one word in s.
All the words in s are separated by a single space.

Solution:

/**
 * @param {string} s
 * @return {string}
 */
var reverseWords = function(s) {
    let st = 0; 
    let en = 0;
    s=s.split('');
    let len = s.length;
    for(let i=0;i<len;i++) {
        if(s[i]==" " && st<en) {
            rev(s,st,en-1);
            st=en+1;
        } else if(i==s.length-1 && st<en){
            rev(s,st,en);
            st=en+1;
        }
        en++;
    }
    
    return s.join('');
}

function rev(str,l,r) {
    while(l<r){
        let tmp = str[l];
        str[l] = str[r];
        str[r] = tmp;
        l++;
        r--;  
    }
}