Leetcode：Implement strStr()

Implement strStr().

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

Update (2014-11-02):
The signature of the function had been updated to return the index instead of the pointer. If you still see your function signature returns a char * or String, please click the reload button to reset your code definition.

子字符串查找问题。

 public int strStr(String haystack, String needle) {        if(haystack==""&&needle=="") return 0;        if(haystack=="") return -1;        if(needle=="") return 0;        for(int i=0;i<=haystack.length()-needle.length();i++){            for(int j=0;j<needle.length();j++){                if(needle.charAt(j)==haystack.charAt(i+j)) {                    if(j==needle.length()-1) return i;                    continue;                }                else break;            }        }        return -1;    }