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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#91717#6137. Sub-cycle GraphLiberty12619WA 196ms4192kbC++201.2kb2023-03-29 14:25:312023-03-29 14:25:33

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.
  • [2023-03-29 14:25:33]
  • 评测
  • 测评结果:WA
  • 用时:196ms
  • 内存:4192kb
  • [2023-03-29 14:25:31]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5+10,mod=1e9+7;
typedef long long LL;
int fact[N],infact[N];
int qmi(int a,int b)
{
    int res=1;
    while(b)
    {
        if(b&1)res=(LL)res*a%mod;
        a=(LL)a*a%mod;
        b>>=1;
    }
    return res;
}
void init()
{
    infact[0]=fact[0]=1;
    for(int i=1;i<N;i++)    fact[i]=(LL)fact[i-1]*i%mod;
    infact[N-1]=qmi(fact[N-1],mod-2);
    for(int i= N-2;i>0;i--) infact[i]=(LL)infact[i+1]*(i+1)%mod;
}
int C(int a,int b)
{
    if(b>a) return 0;
    return (LL)fact[a]*infact[b]%mod*infact[a-b]%mod;
}
void solve()
{
    int n,m;
    cin>>n>>m;
    if(m>n)
    {
        puts("0");
        return;
    }
    if(m==n)
    {
        cout<<fact[n-1]<<endl;
        return ;
    }
    if(m==0)
    {
        puts("1");
        return ;
    }
    int t=1,ans=0;
    for(int i=1;i<=n-m;i++)
    {
        t=(LL)t*(2*i-1)%mod;
        ans=(ans+(LL)C(n,n-m-i)*C(m+i,2*i)%mod*t%mod
        *fact[m-i]%mod*C(m-1,i-1)%mod)%mod;
    }
    //cout<<infact[2]*2%mod<<endl;
    cout<<ans<<endl;
}
int main()
{
    int T =1;
    cin>>T;
    init();
    while(T--)
    {
        solve();
    }
    return 0;
}

详细

Test #1:

score: 100
Accepted
time: 2ms
memory: 4192kb

input:

3
4 2
4 3
5 3

output:

15
12
90

result:

ok 3 number(s): "15 12 90"

Test #2:

score: -100
Wrong Answer
time: 196ms
memory: 4192kb

input:

17446
3 0
3 1
3 2
3 3
4 0
4 1
4 2
4 3
4 4
5 0
5 1
5 2
5 3
5 4
5 5
6 0
6 1
6 2
6 3
6 4
6 5
6 6
7 0
7 1
7 2
7 3
7 4
7 5
7 6
7 7
8 0
8 1
8 2
8 3
8 4
8 5
8 6
8 7
8 8
9 0
9 1
9 2
9 3
9 4
9 5
9 6
9 7
9 8
9 9
10 0
10 1
10 2
10 3
10 4
10 5
10 6
10 7
10 8
10 9
10 10
11 0
11 1
11 2
11 3
11 4
11 5
11 6
11 7
11...

output:

1
3
3
2
1
6
15
12
6
1
10
45
90
60
24
1
15
105
375
630
360
120
1
21
210
1155
3465
5040
2520
720
1
28
378
2940
13545
35280
45360
20160
5040
1
36
630
6552
42525
170100
393120
453600
181440
40320
1
45
990
13230
114345
643545
2286900
4762800
4989600
1814400
362880
1
55
1485
24750
273735
2047815
10239075
...

result:

wrong answer 4th numbers differ - expected: '1', found: '2'