#28 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.

还是Easy Mode.直接上代码

public class Solution {
public int strStr(String haystack, String needle) {
if(needle.length()>haystack.length())return -1;
if(needle.length()==0)return 0;
for(int i=0;i<=haystack.length()-needle.length();i++){
int j=0;
while(haystack.charAt(i+j)==needle.charAt(j)){
if(j==needle.length()-1)return i;
j++;
}
//i=i+j;
}
return -1;
}
}

本想通过i=i+j进行剪枝减少重复，不过有点问题，懒的多想了，就这吧。