【Leetcode】Length of Last Word

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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.

思路：從後往前搜尋直到第一個空格字元，注意“a ”的結果是1而不是0，因此需要先排除最後的空格字元。

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