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 ;
         if(haystack.size() < needle.size()) return -;
         for(int i = ; i <= haystack.size() - needle.size(); ++i){
             int start = i;
             for(int j = ; j < needle.size() && start < haystack.size() && haystack[start] == needle[j]; ++j, ++start){
             }
             if(start-i == needle.size()) return i;
         }
         return -;
     }
 };