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LeetCode Implement strStr()

Implement strStr().

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

 

 1 public class Solution { 2     public String strStr(String haystack, String needle) { 3         if (haystack.equals(needle)) { 4             return haystack; 5         }         6         int haylen=haystack.length(); 7         int neelen=needle.length(); 8         if (neelen>haylen) { 9             return null;10         }11         12         int i,j=0;13         int phay=0;14         while (phay<haylen-neelen) {15             i=phay;16             j=0;17             while (j<neelen && i<haylen && needle.charAt(j)==haystack.charAt(i)) {18                 ++j;19                 ++i;20             }21             if (j==neelen) {22                 return haystack.substring(phay);23             }24             ++phay;25             26         }27         return null;28     }29 }

 

LeetCode Implement strStr()