Submission #740595

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Source Code Expand

#include <iostream>

using namespace std;


long long ncr(int, int);
unsigned int pascal[901][901]={};
int MOD=1000000007;


int D, L, N;

int main(void){
    long long R, C;
    int X, Y;

    cin >> R >> C >> X >> Y >> D >> L;

    int i, j;
    N = D + L;

    for (i=0; i<X*Y+1; i++) {
        pascal[i][0] = 1;

        for (j=1; j<=i&&j<=N; j++) {
            pascal[i][j] = pascal[i-1][j-1] + pascal[i-1][j];
            pascal[i][j] %= MOD;
        }
    }

    if (X*Y==N) {
        cout << (
            (C-Y+1)*(R-X+1) *
            ncr(N, L)
        ) % MOD << endl;
    } else {
        long long patterns;
        patterns = (
            (
                ncr(X*Y, N) - (
                    2 * (ncr((X-1)*Y, N) + ncr(X*(Y-1), N))
                ) + (
                    ncr((X-2)*Y, N) + ncr(X*(Y-2), N) + 4*ncr((X-1)*(Y-1), N)
                ) - (
                    2 * (ncr((X-2)*(Y-1), N) + ncr((X-1)*(Y-2), N))
                ) + (
                    ncr((X-2)*(Y-2), N)
                )
            ) * ncr(N, L) % MOD * (C-Y+1) % MOD * (R-X+1)
        ) % MOD;
        while (patterns < 0) {
            patterns += MOD;
        }
        cout << patterns << endl;
    }

    return 0;
}


long long ncr(int n, int r){
    if (n<0||r<0||n<r) {
        return 0;
    } else {
        return pascal[n][n-r>r? r:n-r];
    }
}

Submission Info

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