Brexit

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Deque;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Stack;
import java.util.TreeMap;

public class Kilpalaatikko {

    public static void main(String[] args) {
        IO io = new IO();
        int n = io.nextInt();
        int m = io.nextInt();
        int x = io.nextInt();
        int l = io.nextInt();
        ArrayList<Integer>[] tt = new ArrayList[n + 1];
        for (int i = 0; i < n + 1; i++) {
            tt[i] = new ArrayList<>();
        }
        for (int i = 0; i < m; i++) {
            int a = io.nextInt();
            int b = io.nextInt();
            tt[a].add(b);
            tt[b].add(a);
        }
        int[] partn = new int[n + 1];
        for (int i = 1; i < n + 1; i++) {
            partn[i] = tt[i].size();
        }
        Stack<Integer> stack = new Stack();
        stack.add(l);
        boolean[] leav = new boolean[n + 1];
        int[] removed = new int[n + 1];
        if (l == x) {
            io.print("leave");
            io.close();
            return;
        }
        while (!stack.isEmpty()) {
            int g = stack.pop();
            leav[g] = true;
            for (int o : tt[g]) {
                if (leav[o]) {
                    continue;
                }
                removed[o]++;
                if (removed[o] * 2 >= partn[o]) {
                    stack.add(o);
                    leav[o] = true;
                    if (o == x) {
                        io.print("leave");
                        io.close();
                        return;
                    }
                }

            }
        }
        io.print("stay");

        io.close(); // TÄYTYY KUTSUA LOPUKSI, muuten tuloste voi jäädä kirjoittamatta
    }

}

class pari implements Comparable<pari> {

    int x;
    int y;
    int z;

    public pari(int x, int y, int z) {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    public int getX() {
        return x;
    }

    public void setX(int x) {
        this.x = x;
    }

    public int getY() {
        return y;
    }

    public void setY(int y) {
        this.y = y;
    }

    @Override
    public int compareTo(pari o) {
        return -o.y + this.y;
    }

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED