#P1089. Use FFT
Use FFT
Description
Bobo computes the product P(x) ⋅ Q(x) = c0 + c1x + … + cn + mxn + m for two polynomials P(x) = a0 + a1x + … + anxn and Q(x) = b0 + b1x + … + bmxm. Find (cL + cL + 1 + … + cR) modulo (109 + 7) for given L and R.
- 1 ≤ n, m ≤ 5 × 105
- 0 ≤ L ≤ R ≤ n + m
- 0 ≤ ai, bi ≤ 109
- Both the sum of n and the sum of m do not exceed 106.
Input
The input consists of several test cases and is terminated by end-of-file.
The first line of each test case contains four integers n, m, L, R.
The second line contains (n + 1) integers a0, a1, …, an.
The third line contains (m + 1) integers b0, b1, …, bm.
Output
For each test case, print an integer which denotes the reuslt.
1 1 0 2
1 2
3 4
1 1 1 2
1 2
3 4
2 3 0 5
1 2 999999999
1 2 3 1000000000
21
18
5