动态规划记录 [动态更新]

const int md = 998244353;
int a[507][507];
ll dp[507][1007];
int main() {
  int n = read,m = read,p = read,q = read;
  for(int i=1; i<=n; i++) {
    for(int j=1; j<=m; j++) a[i][j] = read;
  }
  dp[1][!a[1][1]] = 1;
  for(int i=1; i<=n; i++) {
    for(int j=1; j<=m; j++) {
      if(i != 1 || j != 1)
      if(a[i][j] == 1) {
        for(int k=i+j-1; k>=0; k--) dp[j][k] = (dp[j][k] + dp[j-1][k]) % md;
      } else {
        for(int k=i+j-1; k>=1; k--) dp[j][k] = (dp[j][k-1] + dp[j-1][k-1]) % md;
        dp[j][0] = 0;
      }
    }
  }
  ll ans = 0;
  for(int i=p; i<=n+m-1-q; i++) ans = (ans + dp[m][i]) % md;
  cout << ans << endl;
  return 0;
}