Shared code

import java.util.*;

public class Main {

	public static void main(String[] args) {
		
		Scanner scn = new Scanner(System.in);
		int n = scn.nextInt();
		int[] result = new int[n];
		int[][] arr = new int[n][3];
		for(int i = 0; i<n; i++) {
			arr[i][0] = scn.nextInt();
			arr[i][1] = scn.nextInt();
			arr[i][2] = i;
		}
		Arrays.sort(arr, (x,y) -> Integer.compare(x[0], y[0]));
		
		Queue<int[]> pq = new PriorityQueue<>(n,(x,y) -> Integer.compare(x[0], y[0]));
		int[] room;
		for(int[] cus: arr) {
			if(!pq.isEmpty() && cus[0] > pq.peek()[0]) {
				room = pq.remove();
				room[0] = cus[1];
			}else {
				room = new int[2];
				room[0] = cus[1];
				room[1] = pq.size()+1;
			}
			pq.add(room);
			result[cus[2]] = room[1];
		}
		System.out.println(pq.size());
		for(int num: result) {
			System.out.print(num + " ");
		}
	}

}