static String isitpossible(int a, int b, int c, int d) {
Pair source = new Pair(a, b);
Pair dest = new Pair(c, d);
list.add(source);
while (!list.isEmpty()) {
Pair pair = list.poll();
if (pair.getX() == dest.getX() && pair.getY() == dest.getY()) return "Yes";
else {
int sum = pair.getX() + pair.getY();
if (sum <= Math.max(c, d)) {
list.add(new Pair(sum, pair.getY()));
list.add(new Pair(pair.getX(), sum));
}
}
}
return "No";
}
public synchronized Pair getPair() {
// Make a copy to keep the original safe:
return new Pair(p.getX(), p.getY());
}