毁灭吧

#include<iostream>
#include<algorithm>
#include<cmath>
#include<numeric>
#include<vector>
#include<iomanip>
#include<queue>
#include<set>
#include<map>
typedef long long ll;
const double eps = 1e-4;
using namespace std; 
int bx, by, cx, cy;

bool check(int x, int y)
{
	if ((abs(x - cx) == 2 && abs(y - cy) == 1) || (abs(cx - x) == 1 && abs(cy - y) == 2))
		return 0;
	return 1;
}

int dp[21][21] = {0};
int main()
{
	dp[0][0] = 1;
	cin >> bx >> by >> cx >> cy;
	for (int i = 0; i <= bx; i++)
		for (int j = 0; j <= by; j++)
		{
			if (i == 0 && j == 0)
				continue;
			if (check(i, j))
			{
				if (i == 0)
					dp[i][j] += dp[i][j - 1];
				else
					if (j == 0)
						dp[i][j] += dp[i - 1][j];
					else
						dp[i][j] += dp[i - 1][j] + dp[i][j - 1];
			}
		}
	cout << dp[bx][by]<<endl;
	return 0;
}

没看出来问题在哪，但思路肯定是没问题的，不改了以后再说