Notes

// Online Java Compiler
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/*
You are given production binaries ( executable ) and you need to develop two apis

1. addCompatibility(int new, int old )
2. isCompatible(int src, int target)


so when a new executable is launched you add compatibilty using the first API

Now the executables can have transitive property
stating if 1 is compatible with 2
and 2 is compatible with 3
1 is also compatible with 3



you need to implement two API

1-> 2,3
2-> 1,3
3-> 2,1

use case
HashMap<Integer, HashSet<Integer>> st;
addCompatibility( 1,2 )
isCompatible( 1,2 ) -> true
*/
import java.util.*;
class HelloWorld {
HashMap<Integer, HashSet<Integer>> mp;

public HelloWorld(){
mp = new HashMap<>();
}
public void addCompatability(int a, int b){
HashSet<Integer> st;
HashSet<Integer> union = new HashSet<>();
union.add(a);
union.add(b);

if(mp.contains(a)){
st = mp.get(a);
st.add(b);
union.addAll(st);
}else{
st = new HashSet<>();
st.add(b);
mp.put(a, st);
}

if(mp.contains(b)){
st = mp.get(b);
st.add(a);
union.add(st);
}else{
st = new HashSet<>();
st.add(a);
mp.put(b, st);
}


for(Integer num : union){
mp.put(num, union);
}


}
public boolean isCompatible(int a, int b){

if(mp.containsKey(a) && mp.containsKey(b)){
HashSet<Integer> st = mp.get(a);

return st.contains(b);
}

return false;
}
public static void main(String[] args) {
HelloWorld hw = new HelloWorld();
hw.mp = new HashMap<>();
System.out.println("Hello, World!");
hw.addCompatibility(1, 2);
System.out.println("Hello, World!");
}
}