LeetCode 58. Length of Last Word

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.

题意，找到，最后一个' '后面的单词，求出它的长度，如果没有，就返回0。

思路：从后向前遍历，发现是字母了，触发标识位，如果还是字母继续，发现' '直接停止，返回刚才的单词的长度。

java代码：

public int lengthOfLastWord(String s) { 
        if(s==null || s.length() == 0)
            return 0;
     
        int result = 0;
        int len = s.length();
     
        boolean flag = false;
        for(int i=len-1; i>=0; i--){
            char c = s.charAt(i);
            if((c>='a' && c<='z') || (c>='A' && c<='Z')){
                flag = true;
                result++;
            }else{
                if(flag)
                    return result;
            }
        }
     
        return result;
    }