101963: [AtCoder]ABC196 D - Hanjo
Memory Limit:256 MB
Time Limit:2 S
Judge Style:Text Compare
Creator:
Submit:0
Solved:0
Description
Score : $400$ points
Problem Statement
We have a rectangular room that is $H$ meters long and $W$ meters wide.
We will cover this room with $A$ indistinguishable $2$ meters $\times$ $1$ meters rectangular tatami mats and $B$ indistinguishable $1$ meter $\times$ $1$ meter square tatami mats.
The rectangular mats can be used in either direction: they can be $2$ meters long and $1$ meter wide, or $1$ meter long and $2$ meters wide.
How many ways are there to do this?
Here, it is guaranteed that $2A + B = HW$, and two ways are distinguished if they match only after rotation, reflection, or both.
Constraints
- All values in input are integers.
- $1 ≤ H, W$
- $HW ≤ 16$
- $0 ≤ A, B$
- $2A + B = HW$
Input
Input is given from Standard Input in the following format:
$H$ $W$ $A$ $B$
Output
Print the answer.
Sample Input 1
2 2 1 2
Sample Output 1
4
There are four ways as follows:
Sample Input 2
3 3 4 1
Sample Output 2
18
There are six ways as follows, and their rotations.
Sample Input 3
4 4 8 0
Sample Output 3
36