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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 |
---|---|---|---|---|---|---|---|---|---|
#559096 | #6137. Sub-cycle Graph | pigstd | WA | 125ms | 5996kb | C++20 | 1.6kb | 2024-09-11 20:11:51 | 2024-09-11 20:11:51 |
Judging History
answer
#include<bits/stdc++.h>
#define int long long
#define ull unsigned long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define x first
#define y second
#define vi vector<int>
#define vpi vector<pii>
#define all(x) (x).begin(),(x).end()
using namespace std;
inline int read()
{
char c=getchar();int x=0;bool f=0;
for(;!isdigit(c);c=getchar())f^=!(c^45);
for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
if(f)x=-x;return x;
}
const int Mod=1e9+7;
const int M=1e5+10;
const int inv2=(Mod+1)/2;
int n,T,fac[M],ifac[M],pwiv2[M];
int poww(int a,int b=Mod-2)
{
int res=1;
while(b)
{
if (b&1)res=res*a%Mod;
a=a*a%Mod,b>>=1;
}
return res;
}
void init(int n)
{
fac[0]=pwiv2[0]=1;
for (int i=1;i<=n;i++)fac[i]=fac[i-1]*i%Mod,pwiv2[i]=pwiv2[i-1]*inv2%Mod;
ifac[n]=poww(fac[n]);
for (int i=n;i>=1;i--)ifac[i-1]=ifac[i]*i%Mod;
}
int C(int m,int n)
{
if (n<0||m<n)return 0;
return fac[m]*ifac[n]%Mod*ifac[m-n]%Mod;
}
int calc(int m,int n)
{
if (m<2*n)return 0;
if (n==0)return m==0;
return C(m-n-1,n-1);
}
signed main()
{
init(1e5);
int T=read();
while(T--)
{
int n=read(),m=read();
if (m>n)
{
puts("0");
continue;
}
if (m==n)
{
cout<<fac[n-1]/2<<'\n';
continue;
}
int ans=0;
int k=n-m;
for (int i=0;i<=k;i++)
ans=(ans+pwiv2[k-i]*fac[n-i]%Mod*C(n,i)%Mod*ifac[k-i]%Mod*calc(n-i,k-i))%Mod;
cout<<ans<<'\n';
}
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 2ms
memory: 5996kb
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: 125ms
memory: 5928kb
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:
wrong answer 130th numbers differ - expected: '589145299', found: '89145295'