LeetCode28-实现strStr()

通过切割字符串实现

public int strStr(String haystack, String needle) {
        int n = needle.length();
        if (n == 0) {
            return 0;
        }
        //haystack = "hello", needle = "ll"
        for (int i = 0; i < haystack.length(); i++) {
            if (i + n <= haystack.length() && haystack.substring(i, i + n).equals(needle)) {
                return i;
            }
        }
        return -1;
    }