LeetCode 58. Length of Last Word

58. Length of Last Word

Difficulty: Easy

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

Language: Java

Beats 80%

class Solution {
      public int lengthOfLastWord(String s) {
            if (s == null || s.length() == 0) {
                  return 0;
            }
            s = s.trim();
            if (s.length() == 0) {
                  return 0;
           }
            String[] arr = s.split(" ");
            return arr[arr.length - 1].length();
     }
}

Beats 100%

class Solution {
    public int lengthOfLastWord(String s) {
        if (s == null || s.length() == 0) {
            return 0;
        }
        int i = s.length() - 1;
        while (i >= 0 && s.charAt(i) == ' ') {
            i--;
        }
        if (i < 0) {
            return 0;
        }
        int end = i;
        while (i >= 0 && s.charAt(i) != ' ') {
            i--;
        }
        return end - i;
    }
}