P16722 [CodeChef] CHEFORA
提高-
题目描述

Read problem statements in [Bengali], [Mandarin Chinese], [Russian], and [Vietnamese] as well.

Chef and his friend Bharat have decided to play the game "The Chefora Spell".

In the game, a positive integer N (in decimal system) is considered a "Chefora" if the number of digits d is odd and it satisfies the equation $N = \sum_{i=0}^{d-1} N_{i} \cdot 10^{i}$,

where N_{i} is the i-th digit of N from the left in 0-based indexing.

Let A_{i} denote the i-th smallest Chefora number.

They'll ask each other Q questions, where each question contains two integers L and R. The opponent then has to answer with

$(\prod_{i=L+1}^R (A_{L})^{A_{i}}) \bmod{10^{9}+7}$.

Bharat has answered all the questions right, and now it is Chef's turn. But since Chef fears that he could get some questions wrong, you have come to his rescue!

------ Input Format ------

  • The first line contains an integer Q - the number of questions Bharat asks.
  • Each of the next Q lines contains two integers L and R.

------ Output Format ------

Print Q integers - the answers to the questions on separate lines.

------ Constraints ------

$1 ≤ Q ≤ 10^{5}$
$1 ≤ L < R ≤ 10^{5}$

------ subtasks ------

Subtask #1 (30 points):
$1 ≤ Q ≤ 5 \cdot 10^{3}$
$1 ≤ L < R ≤ 5 \cdot 10^{3}$

Subtask #2 (70 points): Original constraints

----- Sample Input 1 ------
2
1 2
9 11
----- Sample Output 1 ------
1
541416750
----- explanation 1 ------
- For the first question:
$$(A_{1})^{A_{2}}=1^{2}=1.$$

  • For the second question:
    $$(A_{9})^{A_{10}}\cdot (A_{9})^{A_{11}}=9^{101}\cdot 9^{111}\equiv 541416750 \pmod{10^{9}+7}.$$
输入格式

见题面

输出格式

见题面

样例输入
2 1 2 9 11
样例输出
1 541416750