[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.

思路：没用KMP，直接字符串比较，O（m*n）

class Solution {
public:
int strStr(char *haystack, char *needle) {

int hayLen = strlen(haystack);
int needLen= strlen(needle);

for(int i = 0; i <= hayLen-needLen; i++)
{
int k = i;
int j = 0;
for(/* */; j <needLen; /* */)
{
if(haystack[k] == needle[j])
{
k++;
j++;
}
else
break;
}
if(j == needLen)
return i;
}
return -1;

}
};