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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 |
---|---|---|---|---|---|---|---|---|---|
#105251 | #6137. Sub-cycle Graph | Sorting# | WA | 187ms | 5624kb | C++ | 1.2kb | 2023-05-13 19:59:13 | 2023-05-13 19:59:14 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int iu=1e5;
ll f[100001],inf[100001];
ll ph[100001];
ll pw(ll x,ll y){
if(y==0) return 1;
if(y%2) return x*pw(x,y-1)%mod;
ll res=pw(x,y/2);
return res*res%mod;
}
ll C(int x,int y){
if(y<0 || y>x) return 0;
return f[x]*inf[y]%mod*inf[x-y]%mod;
}
ll inv(int d){
return f[d-1]*inf[d]%mod;
}
ll n,m;
void solve(){
cin >> n >> m;
if(m>n){
cout << "0\n";
return;
}
if(m==n){
cout << f[n-1] << '\n';
return;
}
ll ans=0;
for(int k=0; k<n-m ;k++){
ll w1=C(n,k);
ll w2=f[n-k-1];//arrange into cycle
ll rep=inv(m)*(n-k)%mod*C(m,n-k-m)%mod;//arrange m*1 and (n-k-m)*0 in a circle so that no two 0 adjacent
ll cur=w1*w2%mod*rep%mod*ph[n-k-m]%mod*inf[n-k-m-1]%mod;
ans=(ans+cur)%mod;
//cout << n << ' ' << k << ' ' << w1 << ' ' << w2 << ' ' << rep << ' ' << cur << endl;
}
cout << ans << '\n';
}
int main(){
ios::sync_with_stdio(false);cin.tie(0);
f[0]=1;
for(int i=1; i<=iu ;i++) f[i]=f[i-1]*i%mod;
inf[iu]=pw(f[iu],mod-2);
for(int i=iu; i>=1 ;i--) inf[i-1]=inf[i]*i%mod;
ph[0]=1;
for(int i=1; i<=iu ;i++) ph[i]=ph[i-1]*(mod+1)/2%mod;
int t;cin >> t;
while(t--) solve();
}
詳細信息
Test #1:
score: 100
Accepted
time: 5ms
memory: 5604kb
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: 187ms
memory: 5624kb
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:
0 3 3 2 0 6 15 12 6 0 10 45 90 60 24 0 15 105 375 630 360 120 0 21 210 1155 3465 5040 2520 720 0 28 378 2940 13545 35280 45360 20160 5040 0 36 630 6552 42525 170100 393120 453600 181440 40320 0 45 990 13230 114345 643545 2286900 4762800 4989600 1814400 362880 0 55 1485 24750 273735 2047815 10239075 ...
result:
wrong answer 1st numbers differ - expected: '1', found: '0'