Submission #1692521


Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll N = 4010, mod = 1000000007, inv2 = mod + 1 >> 1, M = N * 5;
ll a[M], b[M], fac[N << 1], n, x, inv[N << 1], ans, num[N][N];
ll qow(ll a, ll b)
{
	ll ans = 1;
	for (; b; b >>= 1)
	{
		if (b & 1)
			ans = ans * a % mod;
		a = a * a % mod;
	}
	return ans;
}
ll f(ll i, ll j)
{
	return fac[i + j] * inv[i] % mod * inv[j] % mod;
}
ll& upd(ll &a, ll b)
{
	a = a + b < mod ? a + b : a + b - mod;
	return a;
}
int main()
{
	fac[0] = 1;
	for (ll i = 1; i < 8001; i++)
		fac[i] = fac[i - 1] * i % mod;
	inv[8000] = qow(fac[8000], mod - 2);
	for (ll i = 7999; i >= 0; i--)
		inv[i] = inv[i + 1] * (i + 1) % mod;
	scanf("%lld", &n);
	for (ll i = 1; i <= n; i++)
	{
		scanf("%lld%lld", a + i, b + i);
		num[2000 - a[i]][2000 - b[i]]++;
	}
	for (ll i = 0; i < 4001; i++)
		for (ll j = 0; j < 4001; j++)
		{
			if (i)
				upd(num[i][j], num[i - 1][j]);
			if (j)
				upd(num[i][j], num[i][j - 1]);
		}
	for (ll i = 1; i <= n; i++)
	{
		upd(ans, num[a[i] + 2000][b[i] + 2000]);
		upd(ans, mod - f(a[i] * 2, b[i] * 2));
	}
	cout << ans * inv2 % mod;
}

Submission Info

Submission Time
Task E - BBQ Hard
User c313827
Language C++14 (GCC 5.4.1)
Score 0
Code Size 1163 Byte
Status RE
Exec Time 133 ms
Memory 125696 KB

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:34:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld", &n);
                   ^
./Main.cpp:37:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld%lld", a + i, b + i);
                                  ^

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 0 / 1400
Status
AC × 1
AC × 5
RE × 11
Set Name Test Cases
Sample sample-01.txt
All sample-01.txt, 01-01.txt, 01-02.txt, 01-03.txt, 01-04.txt, 01-05.txt, 01-06.txt, 01-07.txt, 01-08.txt, 01-09.txt, 01-10.txt, 01-11.txt, 01-12.txt, 01-13.txt, 01-14.txt, sample-01.txt
Case Name Status Exec Time Memory
01-01.txt AC 93 ms 125696 KB
01-02.txt AC 94 ms 125696 KB
01-03.txt RE 129 ms 63104 KB
01-04.txt RE 130 ms 63232 KB
01-05.txt RE 130 ms 63232 KB
01-06.txt RE 111 ms 640 KB
01-07.txt AC 93 ms 125696 KB
01-08.txt RE 110 ms 2688 KB
01-09.txt RE 111 ms 2688 KB
01-10.txt RE 122 ms 32128 KB
01-11.txt RE 121 ms 32128 KB
01-12.txt RE 111 ms 9344 KB
01-13.txt RE 133 ms 63104 KB
01-14.txt RE 130 ms 63232 KB
sample-01.txt AC 92 ms 125696 KB