[leetcode]Implement strStr()

问题描述：

Implement strStr().

Returns a pointer to the first occurrence of needle in haystack, ornull if needle is not part of haystack.

代码：

public class Implement_strStr {  //javapublic String strStr(String haystack, String needle) {if(haystack == null || needle == null)            return null;int pos = haystack.indexOf(needle);if(pos == -1)return null;return haystack.substring(pos);    }}