public class Solution {
    public int strStr(String haystack, String needle) {
        int hslen=haystack.length();
        int nllen=needle.length();
        int rlen=-1;
        for(int i=0;i<hslen;i++){
            int len=0;
            for(int j=0;j<nllen;j++){
               int templen=i+j;
               if(templen>=hslen)break;
               if(needle.charAt(j)!=haystack.charAt(templen)){
                   break;
               }else{
                   len++;
               }
            }
            if(len==nllen) {rlen=i;break;}
        }
        return rlen;
    }
}

public class Solution {
    public int strStr(String haystack, String needle) {
       int hlen=haystack.length();
       int nlen=needle.length();
       if(nlen>hlen)return -1;
       int i,j;
       for(i=j=0;i<hlen&&j<nlen;){
           if(haystack.charAt(i)==needle.charAt(j)){
               i++;
               j++;
           }else{
               i=i-j+1;
               j=0;
           }
       }
       return nlen!=j?-1:i-j;
    }
}

public class Solution {
    public int strStr(String haystack, String needle) {
        return  haystack.indexOf(needle);  
    }
}