Очереди с приоритетами stepik

MaxPQ.java

import java.util.Scanner;
import java.util.Arrays;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        MaxPQ pq = new MaxPQ();
        int cnt = 0;
        while (cnt < n) {
            String operation = sc.nextLine();
            if (operation == null || operation.isEmpty()) {
                continue;
            }
            cnt++;
            //System.out.println(operation);
            String[] split = operation.split(" ");
            //System.out.println(Arrays.toString(split));
            if (split.length == 2) {
                pq.insert(Integer.valueOf(split[1]));
            } else {
                System.out.println(pq.delMax());
            }
        }
    }
}

class MaxPQ {
    private Integer[] pq;
    private Integer n;

    public MaxPQ(int capacity) {
        pq = new Integer[capacity + 1];
        n = 0;
    }

    public MaxPQ() {
        this(1);
    }

    public boolean isEmpty() {
        return n == 0;
    }

    public Integer size() {
        return n;
    }

    public Integer max() {
        return pq[1];
    }

    public void insert(int x) {
        if (n == pq.length - 1) resize(pq.length * 2);

        pq[++n] = x;
        swim(n);
    }

    public Integer delMax() {
        Integer max = pq[1];
        swap(1, n--);
        sink(1);
        pq[n + 1] = null;
        if ((n > 0) && (n == (pq.length - 1) / 4)) resize(pq.length / 2);
        return max;
    }

    private void resize(int capacity) {
        Integer[] temp = new Integer[capacity];
        if (n >= 0) System.arraycopy(pq, 1, temp, 1, n);
        pq = temp;
    }

    private void swim(int k) {
        while (k > 1 && less(k / 2, k)) {
            swap(k / 2, k);
            k = k / 2;
        }
    }

    private void sink(int k) {
        while (2 * k <= n) {
            int j = k * 2;
            if (j < n && less(j, j+1)) j++;
            if (!less(k, j)) break;
            swap(k, j);
            k = j;
        }
    }

    private boolean less(int i, int j) {
        return pq[i] < pq[j];
    }

    private void swap(int i, int j) {
        int temp = pq[i];
        pq[i] = pq[j];
        pq[j] = temp;
    }
}