记搜求调

#include <bits/stdc++.h>
#define AKIOI ios::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define AKNOI return 0
#define int long long
#define endl "\n"
using namespace std;
const int N = 5e3 + 100;
const int TMP = 30;
int a[N + TMP][N + TMP], g[N + TMP][N + TMP], f[N + TMP][N + TMP];
int n, m;
int dfs(int x, int y) {
	if (f[x + TMP][y + TMP]) return f[x + TMP][y + TMP];
	if (y == 0 && g[x + TMP][y + TMP] == 0) return f[x + TMP][y + TMP] = 1;
	else if (g[x + TMP][y + TMP] == 0) return f[x + TMP][y + TMP] = dfs(x - 1, y) + dfs(x, y - 1);
}
void book(int x, int y) {
	g[x - 1 + TMP][y - 2 + TMP] = 1; //加一个向右偏移量，防止越界
	g[x - 2 + TMP][y - 1 + TMP] = 1;
	g[x - 2 + TMP][y + 1 + TMP] = 1;
	g[x - 1 + TMP][y + 2 + TMP] = 1;
	g[x + 1 + TMP][y - 2 + TMP] = 1;
	g[x + 2 + TMP][y - 1 + TMP] = 1;
	g[x + 1 + TMP][y + 2 + TMP] = 1;
	g[x + 2 + TMP][y + 1 + TMP] = 1;
	g[x + TMP][y + TMP] = 1;
}
signed main() {
	AKIOI;
	int x, y;
	cin >> n >> m >> x >> y;
	book(x, y);
	for (int i = 0; i <= n && g[i + TMP][0 + TMP] == 0; i ++) f[i + TMP][0 + TMP] = 1;
	for (int i = 0; i <= m && g[0 + TMP][i + TMP] == 0; i ++) f[0 + TMP][i + TMP] = 1;
	cout << dfs(n, m);
	AKNOI;
}