P12828 「DLESS-2」XOR and Number Theory
Description
Given two integers $n$ and $m$. You need to find the sum of $x^2\bmod(y^2-xy)$ over all pairs of integers $(x,y)$ that satisfy the following two conditions:
- $1\le x< y\le n$
- $x\oplus y=\gcd(x,y)\le m$
Here, $\oplus$ denotes the bitwise XOR operation.
Since the result can be very large, output the answer modulo $10^9+7$.
Input Format
There are multiple test cases. The first line contains a single positive integer $T$, indicating the number of test cases.
For each test case, there is a single line containing two integers, $n$ and $m$.
Output Format
For each test case, output a single line containing one integer, representing the answer modulo $10^9+7$.
Explanation/Hint
For all test data, it is guaranteed that:
- $1\le T\le 3000$
- $2\le n\le 10^9$
- $1\le m\le n$
- $1\le \sum m\le 10^5$
**This problem uses subtasks for grading.** The description for each subtask is as follows:
| Subtask | $n\le$ | $\sum n\le$ | $\sum m\le$ | Points |
| :----------: | :----------: | :----------: | :----------: | :----------: |
| $1$ | $1000$ | $1000$ | $1000$ | $10$ |
| $2$ | $10^4$ | $10^4$ | $10^4$ | $10$ |
| $3$ | $10^7$ | $10^7$ | $10^5$ | $10$ |
| $4$ | $5\times10^7$ | $5\times10^7$ | $10^5$ | $20$ |
| $5$ | $10^9$ | $+\infty$ | $1000$ | $10$ |
| $6$ | $10^9$ | $+\infty$ | $5000$ | $10$ |
| $7$ | $10^9$ | $+\infty$ | $3\times 10^4$ | $10$ |
| $8$ | $10^9$ | $+\infty$ | $10^5$ | $20$ |