Submission #810127

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;
const int N = 2010;
const int MOD = 1e9+7;
int p[2*N][2*N];
int C[4*N][2*N];
int main() {
	for (int i=0;i<4*N;i++)
		for (int j=0;j<=min(i,2*N-1);j++)
			if (i == j) C[i][j] = 1;
			else if (j == 0) C[i][j] = 1;
			else C[i][j] = (C[i-1][j-1] + C[i-1][j]) % MOD; 
	int n;
	int ans = 0;
	int ans2 = 0;
	scanf("%d",&n);
	for (int i=0;i<n;i++) {
		int x,y;
		scanf("%d %d",&x,&y);
		p[N-x][N-y]++;
		p[N+x][N+y]++;
		ans = (ans + C[2*(x+y)][2*x]) % MOD;
	}
	for (int i=1;i<2*N;i++)
		for (int j=1;j<2*N;j++) {
			if (i>N && j>N && p[i][j]) {
				ans2 = ((1ll*p[i][j]*((p[i-1][j] + p[i][j-1]) % MOD)) % MOD + ans2) % MOD;
				p[i][j] = (p[i-1][j] + p[i][j-1]) % MOD;
			}
			else p[i][j] = (1ll*p[i-1][j] + p[i][j-1] + p[i][j]) % MOD;
		}
	ans = (ans2+MOD-ans) % MOD;
	if (ans % 2) ans += MOD;
	printf("%d\n",ans/2);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:16:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:19:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&x,&y);
                       ^

Judge Result