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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#135456#6637. Perfect StringsPlentyOfPenaltyWA 191ms11440kbC++201.1kb2023-08-05 15:38:402023-08-05 15:38:44

Judging History

你现在查看的是最新测评结果

  • [2023-08-10 23:21:45]
  • System Update: QOJ starts to keep a history of the judgings of all the submissions.
  • [2023-08-05 15:38:44]
  • 评测
  • 测评结果:WA
  • 用时:191ms
  • 内存:11440kb
  • [2023-08-05 15:38:40]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
using ll=long long;
const int N=1e3+9,mod=1e9+7;
int T,n,c,ans,a[N],fac[N],C[(N<<1)][N],A[N];
inline int inv(int x){
	if(x<2)return 1;
	return (ll)(mod-mod/x)*inv(mod%x)%mod;
}
void dfs(int u,int s){
	if(u==c){
		int cur=A[n]*fac[n];
		if(s==0){
			for(int i=0;i<c;i++)cur=(ll)cur*inv((ll)A[a[i]]*fac[a[i]]%mod)%mod;
			ans=(ans+cur)%mod;
			// cerr<<">> "<<cur<<endl;
			// for(int i=0;i<c;i++)cerr<<a[i]<<" \n"[i+1==c];
		}
		return;
	}
	for(int x=0;x<=s;x++){
		a[u]=x;
		// cerr<<"cho: "<<u<<" "<<x<<endl;
		dfs(u+1,s-x);
	}
}
int solve(){
	ans=0;
	for(int i=0;i<=n;i++)A[i]=(ll)C[i<<1][i]*inv(i+1)%mod;
	// for(int i=0;i<=n;i++)cerr<<A[i]<<" \n"[i==n];
	dfs(0,n);
	return ans;
}
int main(){
#ifdef memset0
	freopen("G.in","r",stdin);
#endif
	ios::sync_with_stdio(0),cin.tie(0);
	fac[0]=1;
	for(int i=1;i<N;i++)fac[i]=(ll)fac[i-1]*i%mod;
	for(int i=0;i<(N<<1);i++){
		C[i][0]=1;
		for(int j=1;j<=i&&j<N;j++)C[i][j]=(C[i-1][j]+C[i-1][j-1])%mod;
	}
	cin>>T;
	while(T--){
		cin>>n>>c;
		cout<<solve()<<endl;
	}
}

Details

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Test #1:

score: 100
Accepted
time: 3ms
memory: 11388kb

input:

2
3 1
2 2

output:

1
6

result:

ok 2 number(s): "1 6"

Test #2:

score: -100
Wrong Answer
time: 191ms
memory: 11440kb

input:

100000
1 1
4 1
5 5
3 5
1 2
5 3
1 1
3 3
5 2
2 1
4 1
5 5
2 3
4 1
3 3
2 5
3 2
4 3
4 4
3 5
3 1
5 2
2 2
4 2
5 4
1 2
3 1
4 5
2 5
5 3
1 5
5 2
3 2
5 2
4 1
1 3
3 2
4 5
2 1
4 1
2 2
1 1
3 5
4 5
2 3
3 5
2 5
2 4
5 4
2 3
1 1
2 1
4 4
1 5
5 4
1 3
5 4
4 5
1 3
1 1
3 3
2 4
2 4
2 1
5 5
1 3
2 3
4 1
4 3
2 4
2 4
4 2
1 1
1...

output:

1
1
45875
455
2
1794
1
78
116
1
1
45875
15
1
78
45
17
400000388
800001614
455
1
116
6
800000051
11524
2
1
4639
45
1794
5
116
17
116
1
3
17
4639
1
1
6
1
455
4639
15
455
45
28
11524
15
1
1
800001614
5
11524
3
11524
4639
3
1
78
28
28
1
45875
3
15
1
400000388
28
28
800000051
1
1
45875
15
800001614
3
1
2...

result:

wrong answer 3rd numbers differ - expected: '71445', found: '45875'