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.
1 public class Solution { 2 public int strStr(String haystack, String needle) 3 { 4 if(needle.length()==0) 5 return 0; 6 7 for (int i=0;i<haystack.length();i++) 8 { 9 if (haystack.length() - i +1 < needle.length()) 10 return -1; 11 12 int j = 0; 13 int k = i; 14 15 while(j<needle.length()&&k<haystack.length()&&needle.charAt(j)==haystack.charAt(k)) 16 { 17 j++; 18 k++; 19 if(j==needle.length()) 20 return i; 21 } 22 23 } 24 25 return -1; 26 } 27 }
原文：http://www.cnblogs.com/hygeia/p/4903336.html