58. Length of Last Word

Problem

Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

Example:

Input: "Hello World"
Output: 5

Solution

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLastWord = function(s) {
  var str = s.trim();
  var len = str.length;
  var i = len - 1;
  while (i >= 0 && str[i] !== ' ') i--;
  return len - 1 - i;
};

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(1).