hello,

"hi" is only printed when both ifs are true.
Is that your problem? Then check / correct the ifs (see other thread)

Or do you mean you want to check all items in the arrays and when ifs are true one or more time then print hi only once?
That would be this:

1. String[] a = split(trim(serial), ',');  //a new array (called 'a') that stores values into separate cells (separated by commas specified in  Arduino program)
2. 
   
3. boolean              found=false;
   
   
4.    int s2 = int(map(int(a[1]),1,1023,1,400));
5.    int s1 = int(map(int(a[0]),1,1023,1,1023));
6. 
   
7.  for (int j = 1; j <109; j++) {
8.       if (s1==x[j]){
9.         for(int i=1; i<400 ; i++){
10.             if(s2==y[i]){     
11.      
12.              found=true;
    
13. 
    
14.           }
15.        }
16.    }
17.  }
18. 
    
19. if (found)
20.           println("Hi");

Greetings, Chrisir