[leetcode]32 Length of Last Word

タイトルリンク:https://leetcode.com/problems/length-of-last-word/ Runtimes:4ms
1、問題
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.
2、分析
簡単な問題、境界の判断に注意する
3、まとめ
トラップ:1、空の文字列判断;2、i境界の判断
4、実現

class Solution {
public:
    int lengthOfLastWord(const char *s) {
        if('\0' == s[0])
            return 0;
        int i = 0;
        while(s[i] != '\0')
            ++i;
        --i;
        while(i >= 0 && s[i] == ' ')
            --i;
        int sta = i;
        while(i >= 0 && s[i] != ' ')
            --i;
        return sta - i;
    }
};

5、反省
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