AtCoder Beginner Contest 154
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Problem Statement
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Snuke is standing on a two-dimensional plane. In one operation, he can move by $1$ in the positive $x$-direction, or move by $1$ in the positive $y$-direction.
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Let us define a function $f(r, c)$ as follows:
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$f(r,c) :=$(The number of paths from the point$(0, 0)$to the point$(r, c)$that Snuke can trace by repeating the operation above)
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Given are integers $r_1$, $r_2$, $c_1$, and $c_2$. Find the sum of $f(i, j)$ over all pair of integers $(i, j)$ such that $r_1 ≤ i ≤ r_2$ and $c_1 ≤ j ≤ c_2$, and compute this value modulo $(10^9+7)$.
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Constraints
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$1 ≤ r_1 ≤ r_2 ≤ 10^6$$1 ≤ c_1 ≤ c_2 ≤ 10^6$- All values in input are integers.
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Input
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Input is given from Standard Input in the following format:
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r_1 c_1 r_2 c_2
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Output
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Print the sum of $f(i, j)$ modulo $(10^9+7)$.
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样例
Input #1
1 1 2 2
Output #1
14
For example, there are two paths from the point $(0, 0)$ to the point $(1, 1)$: $(0,0)$ → $(0,1)$ → $(1,1)$ and $(0,0)$ → $(1,0)$ → $(1,1)$, so $f(1,1)=2$.
Similarly, $f(1,2)=3$, $f(2,1)=3$, and $f(2,2)=6$. Thus, the sum is $14$.
Input #2
314 159 2653 589
Output #2
602215194
题目信息
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。