题解 | #[NOIP2002 普及组] 过河卒#

#include <iostream>
using namespace std;

int main() {

    int n, m, x, y;
    cin >> n >> m >> x >> y;
    x += 1; y+=1;
    long arr[25][25] = {0};
    arr[0][1] = 1;
    for (int i = 1; i <= n+1; i++) {
        for (int j = 1; j <= m+1; j++) {
           if(i!=x && j!=y && abs(i-x)+abs(j-y)==3 || (i==x &&j==y))
           {
                arr[i][j]=0;
           }
           else {
                arr[i][j] += arr[i - 1][j] + arr[i][j - 1];
           }
            
        }
    }
    cout << arr[n+1][m+1] << endl;
    return 0;

}