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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#533904#6137. Sub-cycle GraphTomato_Fish#AC ✓159ms5032kbC++141.3kb2024-08-26 16:32:412024-08-26 16:32:41

Judging History

你现在查看的是最新测评结果

  • [2024-08-26 16:32:41]
  • 评测
  • 测评结果:AC
  • 用时:159ms
  • 内存:5032kb
  • [2024-08-26 16:32:41]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e5+100,mod=1e9+7,maxn=1e5;

int fl[N],nf[N],Mi[N];

int mi(int x,int t){
    int d=1;
    while(t){
        if(t%2) d=(ll)d*x%mod;
        x=(ll)x*x%mod;t/=2;
    }
    return d;
}
int ni(int x) {return mi(x,mod-2);}

int C(int n,int m){
    if(m<0||m>n) return 0;
    return (ll)fl[n]*nf[m]%mod*nf[n-m]%mod;
}

int main()
{

    fl[0]=1;for(int i=1;i<=maxn;i++) fl[i]=(ll)fl[i-1]*i%mod;
    nf[maxn]=ni(fl[maxn]);for(int i=maxn-1;i>=0;i--) nf[i]=(ll)nf[i+1]*(i+1)%mod;

    int Ntwo=ni(2);
    Mi[0]=1;for(int i=1;i<=maxn;i++) Mi[i]=(ll)Mi[i-1]*Ntwo%mod;

    int T;scanf("%d",&T);

    while(T--){
        int n;ll m;
        scanf("%d%lld",&n,&m);

        if(n==m){
            printf("%d\n",(ll)fl[n-1]*Ntwo%mod);
            continue;
        }

        if(m>n){
            printf("0\n");
            continue;
        }

        if(m==0){
            printf("1\n");
            continue;
        }

        int Ans=0;
        for(int i=1;i<=n/2&&i<=n-m&&i<=m;i++){
            int t=(ll)C(n,m+i)*C(m+i,2*i)%mod*fl[2*i]%mod*Mi[i]%mod*fl[m-i]%mod*C(m-1,i-1)%mod*nf[i]%mod;
            Ans=(Ans+t)%mod;
        }
        printf("%d\n",Ans);

    }

    return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 2ms
memory: 4984kb

input:

3
4 2
4 3
5 3

output:

15
12
90

result:

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

Test #2:

score: 0
Accepted
time: 159ms
memory: 5032kb

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

result:

ok 17446 numbers