leetcode: 28. Implement strStr()

Difficulty

Easy

Description

Implement strStr().

Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

Example 1:

Input: haystack = "hello", needle = "ll"
Output: 2
Example 2:

Input: haystack = "aaaaa", needle = "bba"
Output: -1

Solution

class Solution {
    public int strStr(String haystack, String needle) {
        if (needle.length() == 0) return 0;
        for (int i = 0; i <= haystack.length() - needle.length(); i++)
        {
			if (needle.equals(haystack.substring(i, i + needle.length())))
				return i;
        }
		return -1;
    }
}