Binomial Sum of Products
Practice
3.2 (15 votes)
Dynamic programming
Easy
Pascal's rule
Pascal's rule
Two dimensional
Problem
20% Success 6134 Attempts 20 Points 1s Time Limit 256MB Memory 1024 KB Max Code
A function \(f(x,y)\) is defined as
\(f(x,y) = \binom{x}{y}\) if \(x \geq y\) else x x y
where \(\binom{x}{y} = \frac{x!}{y!(x-y)!}\)
There will be total q queries and each query will have four integers i.e. a, b, c and d. You need to compute the value of
\(\sum_{i = a}^b \prod_{j=c}^d\) \(f(i,j)\) for every query.
As the output number can be very large. So, you need to print answer modulo \(10^9+7\)
Note: \(0!=1\)
Input Format
- First line will have a single integer denoting the value of q.
- Each line in next q lines will have four space separated integers denoting the value of a,b,c and d.
Output Format
- Output q lines, where \(i^{th}\) line denoting the answer represents the answer of the \(i^{th}\) query modulo \(10^9+7\).
Constraints
- \(1\leq q \leq 1000\)
- \(0 \leq a \leq b \leq 1000\)
- \(0 \leq c \leq d \leq 1000\)
Submissions
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