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.

水题，从字符串最后开始往前判断就完了。

class Solution {
public:
    int lengthOfLastWord(const char *s) {
		int cnt=0;
		for(int i=strlen(s)-1;i>=0;){
			if(s[i]==' '){
				while(s[i]==' '&&i>=0) i--;
			}
			else{
				while(s[i]!=' '&&i>=0) {cnt++;i--;}
				break;
			}
		}
		return cnt;        
    }
};