LeetCode OJ：Implement strStr()（实现子字符串查找）

Implement strStr().

Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

额，当然我用的就是暴力搜索来，没用到KMP之类的算法，有时间再来补上辣，代码如下：

class Solution {
public:
    int strStr(string haystack, string needle) {
        if(!needle.size()) return 0;
        if(haystack.size() < needle.size()) return -1;
        for(int i = 0; i <= haystack.size() - needle.size(); ++i){
            int start = i;
            for(int j = 0; j < needle.size() && start < haystack.size() && haystack[start] == needle[j]; ++j, ++start){
            }
            if(start-i == needle.size()) return i;
        }
        return -1;
    }
};