#P9331. [JOIST 2023] 护照 / Passport

[JOIST 2023] 护照 / Passport

Description

Passport is a certificate which is used worldwide when a traveler enters foreign countries.

In a planet, there are NN countries, numbered from 11 to NN. Each country issues a passport. When a traveler has a passport issued by the country i (1iN)i \ (1 \le i \le N), the traveler can enter the countries Li,Li+1,,RiL_i, L_i + 1, \dots, R_i. Here, it is guaranteed that the traveler can enter the country where the passport was issued. Namely, LiiRiL_i \le i \le R_i is satisfied.

You have a friend who likes traveling. Although he dreams of traveling around the world, he does not have a passport in the beginning. Thus, he plans to visit all of the NN countries by repeating the following two actions.

  • He gets a passport issued by the country where he is currently staying.
  • He moves to a country where he can enter using a passport he currently has.

When you hear about his plan, you are wondering whether it is possible to realize the plan, and, if it is possible, what is the minimum number of passports he needs to get. Since you do not know where he lives, you consider QQ possible countries X1,X2,,XQX_1, X_2, \dots, X_Q where he lives.

Write a program which, given information of the passports and the possibilities of his living place, for each possibility, determines whether it is possible for him to visit all of the NN countries, and, if it is possible, calculates the minimum number of passports he needs to get.

Input Format

Read the following data from the standard input.

NN

L1 R1L_1 \ R_1

L2 R2L_2 \ R_2

\vdots

LN RNL_N \ R_N

QQ

X1X_1

X2X_2

\vdots

XQX_Q

Output Format

Write QQ lines to the standard output. The jj-th line (1jQ)(1 \le j \le Q) corresponds to the case where your friend lives in the country XjX_j. If it is possible for him to visit all of the NN countries, this line should contain the minimum number of passports he needs to get. Otherwise, this line should contain 1-1.

4
1 3
2 4
2 3
4 4
1
1

2

5
1 5
2 4
2 3
3 5
1 5
1
3

4

5
1 1
2 3
1 5
3 4
5 5
5
1
2
3
4
5

-1
2
1
2
-1

4
1 2
1 2
3 4
3 4
4
1
2
3
4

-1
-1
-1
-1

Hint

【样例解释 #1】

Assume that your friend lives in the country X1=1X_1 = 1. It is possible for him to visit all of the 44 countries if he acts in the following way. Then, he gets 22 passports.

  1. He gets a passport issued by the country 11.
  2. Using the passport issued by the country 11, he moves to the country 22.
  3. He gets a passport issued by the country 22.
  4. Using the passport issued by the country 11, he moves to the country 33.
  5. Using the passport issued by the country 22, he moves to the country $44.

Since it is impossible to realize the plan if he gets less than or equal to 11 passport, output 22.

该样例满足所有子任务的限制。

【样例解释 #2】

Assume that your friend lives in the country X1=3X_1 = 3. It is possible for him to visit all of the 55 countries if he acts in the following way. Then, he gets 44 passports.

  1. He gets a passport issued by the country 33.
  2. Using the passport issued by the country 33, he moves to the country 22.
  3. He gets a passport issued by the country 22.
  4. Using the passport issued by the country 22, he moves to the country 44.
  5. He gets a passport issued by the country 44.
  6. Using the passport issued by the country 44, he moves to the country 55.
  7. He gets a passport issued by the country 55.
  8. Using the passport issued by the country 55, he moves to the country 11.

Since it is impossible to realize the plan if he gets less than or equal to 33 passports, output 44.

该样例满足子任务 252 \sim 5 的限制。

【样例解释 #3】

For example, if your friend lives in the country X3=3X_3 = 3, it is possible to realize the plan if he gets a passport issued by the country 33, and uses it to visit the countries 1,2,4,51, 2, 4, 5 in this order. Therefore, output 11 in the third line.

On the other hand, if your friend lives in the country X5=5X_5 = 5, it is impossible for him to enter other countries even if he gets a passport issued by the country 55. Thus, he cannot realize the plan. Therefore, output 1-1 in the fifth line.

该样例满足子任务 454 \sim 5 的限制。

【样例解释 #4】

该样例满足子任务 454 \sim 5 的限制。

【数据范围】

对于所有测试数据,满足 2N2×1052 \le N \le 2 \times 10 ^ 51LiiRiN1 \le L_i \le i \le R_i \le N1QN1 \le Q \le N1X1<X2<<XQN1 \le X_1 < X_2 < \dots < X_Q \le N,保证所有输入均为整数。

子任务编号 分值 限制
11 66 Q=1Q = 1X1=1X_1 = 1
22 1616 N300N \le 300Q=1Q = 1
33 2424 N2500N \le 2500Q=1Q = 1
44 88 N2500N \le 2500
55 4646