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QOJ
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 |
---|---|---|---|---|---|---|---|---|---|
#533904 | #6137. Sub-cycle Graph | Tomato_Fish# | AC ✓ | 159ms | 5032kb | C++14 | 1.3kb | 2024-08-26 16:32:41 | 2024-08-26 16:32:41 |
Judging History
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;
}
詳細信息
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