Implement strStr()

https://leetcode.com/problems/implement-strstr/

Implement strStr().

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

public class Solution {
    public static int strStr(String haystack, String needle) {
        if(needle.equals("")){return 0;}
        int len1=haystack.length();int len2=needle.length();
        for(int i=0;i+len2<=len1;i++){
            if(haystack.charAt(i)!=needle.charAt(0)){continue;}
            boolean flag=true;
            for(int j=1;j<len2;j++){
            if(haystack.charAt(i+j)!=needle.charAt(j)){flag=false;break;}
            }
            if(flag==true){return i;}
        }
        return -1;
    }
    public static void main(String[]args){
    System.out.println(strStr("dddabcfsdf","abc"));
    }
}