Problem:
Score : 600 points

Problem Statement

There is a grid of squares with H+1 horizontal rows and W vertical columns.

You will start at one of the squares in the top row and repeat moving one square right or down. However, for each integer i from 1 through H, you cannot move down from the A_i-th, (A_i + 1)-th, \ldots, B_i-th squares from the left in the i-th row from the top.

For each integer k from 1 through H, find the minimum number of moves needed to reach one of the squares in the (k+1)-th row from the top. (The starting square can be chosen individually for each case.) If, starting from any square in the top row, none of the squares in the (k+1)-th row can be reached, print -1 instead.

Constraints

1 \leq H,W \leq 2\times 10^5

1 \leq A_i \leq B_i \leq W

Input

Input is given from Standard Input in the following format:

H W
A_1 B_1
A_2 B_2
:
A_H B_H

Output

Print H lines. The i-th line should contain the answer for the case k=i.

Sample Input 1

4 4
2 4
1 1
2 3
2 4

Sample Output 1

1
3
6
-1

Let (i,j) denote the square at the i-th row from the top and j-th column from the left.

For k=1, we need one move such as (1,1) → (2,1).

For k=2, we need three moves such as (1,1) → (2,1) → (2,2) → (3,2).

For k=3, we need six moves such as (1,1) → (2,1) → (2,2) → (3,2) → (3,3) → (3,4) → (4,4).

For k=4, it is impossible to reach any square in the fifth row from the top.

Solution in Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Reader sc = new Reader();
        PrintWriter pw = new PrintWriter(System.out);
        
        try {
            int n = sc.nextInt();
            int m = sc.nextInt();
            int l = 1;
            long moves = 0;
            for(int i=0 ; i<n ; i++) {
                int a = sc.nextInt();
                int b = sc.nextInt();
                if(l <= m) {
                    if(l >= a && l <= b) {
                        moves += b-l+1;
                        l = b+1;
                    }
                    moves++;
                    if(l <= m) {
                        pw.println(moves);
                    }
                    else {
                        pw.println(-1);
                    }
                }
                else {
                    pw.println(-1);
                }
            }
        }
        finally {
            pw.flush();
            pw.close();
        }
    }
    
    static class Reader {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer("");

        String next() {
            while(!st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                }
                catch(IOException io) {
                    io.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
}