Length of Last Word | leetcode 58 【Java solving】

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.

For example, 

Given s = "Hello World",

return 5.

【solution】：

It will become easy if we try to find the last word from last char.

【code】：

public class Solution {
    public int lengthOfLastWord(String s) {
		if(s == null)
	        return 0;
	        
	    int len = s.length();
	    int count = 0;
	    for(int i = len - 1; i >= 0; i--) {
	        if(s.charAt(i) != ' ')
	            count++;
	        if(s.charAt(i)==' ' && count != 0)
	            return count;
	    }
	    return count;
	}
}

【 optimization 】：
If we use trim() at first,  the sullution will become easier as following.

public class Solution {
    public int lengthOfLastWord(String s) {
        s = s.trim();
	    int len = s.length();
	    int count = 0;
	    for(int i = len - 1; i >= 0; i--) {
	        if(s.charAt(i) != ' ') count++;
	        else break;
	    }
	    return count;
	}
}

59 / 59  test cases passed.   Runtime: 1 ms

finally, welcome criticism!