AtCoder Beginner Contest 138
F
Coincidence
AtCoder
⌀ 2431
原题
← E→
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Problem Statement

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Given are integers $L$ and $R$. Find the number, modulo $10^9 + 7$, of pairs of integers $(x, y)$ $(L \leq x \leq y \leq R)$ such that the remainder when $y$ is divided by $x$ is equal to $y \text{ XOR } x$.

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What is $\text{ XOR }$? The XOR of integers $A$ and $B$, $A \text{ XOR } B$, is defined as follows: When $A \text{ XOR } B$ is written in base two, the digit in the $2^k$'s place ($k \geq 0$) is $1$ if either $A$ or $B$, but not both, has $1$ in the $2^k$'s place, and $0$ otherwise. For example, $3 \text{ XOR } 5 = 6$. (In base two: $011 \text{ XOR } 101 = 110$.)

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Constraints

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  • $1 \leq L \leq R \leq 10^{18}$
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Input

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Input is given from Standard Input in the following format:

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L R

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Output

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Print the number of pairs of integers $(x, y)$ $(L \leq x \leq y \leq R)$ satisfying the condition, modulo $10^9 + 7$.

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样例

Input #1
2 3
Output #1
3
Three pairs satisfy the condition: $(2, 2)$, $(2, 3)$, and $(3, 3)$.
Input #2
10 100
Output #2
604
Input #3
1 1000000000000000000
Output #3
68038601
Be sure to compute the number modulo $10^9 + 7$.
题目信息
题号
abc138_f
时间限制
2 s
内存限制
1024 MB

题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。