leetcode28实现strStr()

暴力法

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