Submission #3049647


Source Code Expand

#include<cstdio>
#define neko 5010
#define seko 1000010
#define f(i,a,b) for(register int i=(a);i<=(b);i=-(~(i)))
#define rf(i,a,b) for(register int i=(a);i>=(b);i=~(-(i)))
int n,a[seko],b[seko];
typedef long long ll;
ll dp[neko][neko],fac[seko],invfac[seko],ans,mod=1e9+7;
ll slowpow(ll m,ll n)
{
	ll b=1;
	for(;n;n>>=1,m=m*m%mod)if(n&1)b=b*m%mod;
	return b;
}
ll C(ll m,ll n)
{if(n>m)return 0;return fac[m]*invfac[n]%mod*invfac[m-n]%mod;}
ll ADD(ll x,ll y){return (x+=y)>=mod?x-mod:x;}
int main()
{
	scanf("%d",&n);
	f(i,1,n)scanf("%d%d",&a[i],&b[i]),++dp[-a[i]+2000][-b[i]+2000];
	fac[0]=invfac[0]=1;
	f(i,1,10000)fac[i]=fac[i-1]*i%mod;
	invfac[10000]=slowpow(fac[10000],mod-2);
	rf(i,9999,1)invfac[i]=invfac[i+1]*(i+1)%mod;
	f(i,0,4000)
	 f(j,0,4000)
	 {
		if(i)dp[i][j]=ADD(dp[i][j],dp[i-1][j]);
		if(j)dp[i][j]=ADD(dp[i][j],dp[i][j-1]);
	 }
	f(i,1,n)ans=(ans+dp[a[i]+2000][b[i]+2000])%mod;
	f(i,1,n)ans=(ans+mod-C(2*(a[i]+b[i]),2*a[i]))%mod;
	printf("%lld\n",(ans*slowpow(2,mod-2)%mod+mod)%mod);
}

Submission Info

Submission Time
Task E - BBQ Hard
User colldisSavior
Language C++14 (GCC 5.4.1)
Score 1400
Code Size 1037 Byte
Status AC
Exec Time 149 ms
Memory 166144 KB

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:20:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:21:64: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  f(i,1,n)scanf("%d%d",&a[i],&b[i]),++dp[-a[i]+2000][-b[i]+2000];
                                                                ^

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 1400 / 1400
Status
AC × 1
AC × 16
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 165376 KB
01-02.txt AC 89 ms 166144 KB
01-03.txt AC 118 ms 166144 KB
01-04.txt AC 149 ms 166144 KB
01-05.txt AC 149 ms 166144 KB
01-06.txt AC 126 ms 166144 KB
01-07.txt AC 86 ms 166144 KB
01-08.txt AC 120 ms 166144 KB
01-09.txt AC 126 ms 166144 KB
01-10.txt AC 134 ms 166144 KB
01-11.txt AC 136 ms 166144 KB
01-12.txt AC 128 ms 166144 KB
01-13.txt AC 145 ms 166144 KB
01-14.txt AC 146 ms 166144 KB
sample-01.txt AC 86 ms 166144 KB