LeetCode-058：Length of Last Word

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题目：

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

题意：

找出字符串中最后一个单词的长度

思路：

从后往前找，cnt计数，遇到空格判断cnt的值，不为0说明已经算出最后一个单词的长度，返回cnt~一道水题大佬们怎么做的时间复杂度那么低，你们是魔鬼吗？服了，膜拜~Runtime: 8 ms, faster than 4.66% of C++ online submissions for Length of Last Word.

Code：

class Solution {
public:
    int lengthOfLastWord(string s) {
        int cnt=0,i=s.size()-1;
        for(;i>=0;i--){
            if(s[i]!=' ') cnt++;
            else{
                if(cnt) return cnt;
            }
        }
        return cnt;
    }
};