public int strStr(String haystack, String needle) {
		
		if (haystack.length() < needle.length()) return -1;
		if (needle.length() == 0) return 0;
		
		for (int i = 0; i < haystack.length() - needle.length() + 1; i++) {
			
			if (haystack.charAt(i) == needle.charAt(0)) {
				
				int j = 1;
				while (j < needle.length()) {
					if (haystack.charAt(i + j) != needle.charAt(j)) break;
					else j++;
				}
				if (j == needle.length()) return i;
			}
		
		}
		
		return -1;
	}