QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#180453 | #7087. Counting Polygons | brz# | WA | 309ms | 172032kb | C++20 | 3.3kb | 2023-09-15 20:58:08 | 2023-09-15 20:58:08 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
#define maxn 10000010
#define mod 1000000007
int prime[maxn],pt=0;
bool vp[maxn];
int phi[maxn];
void SieveInit(const int N){
phi[1]=1;
for(int i=2;i<=N;i++){
if(!vp[i])prime[++pt] = i, phi[i] = i-1;
for(int j=1;j<=pt&&i*prime[j]<=N;j++){
vp[i*prime[j]] = true;
if(i%prime[j]==0){
phi[i*prime[j]] = phi[i] * prime[j];
break;
}
phi[i*prime[j]] = phi[i] * (prime[j]-1);
}
}
}
int fac[maxn],inv[maxn],inv_fac[maxn];
void FacInit(int N){
fac[0]=inv_fac[0]=inv[1]=1;
for(int i=1;i<=N;i++)fac[i]=1ll*fac[i-1]*i%mod;
for(int i=2;i<=N;i++)inv[i]=1ll*(mod-mod/i)*inv[mod%i]%mod;
for(int i=1;i<=N;i++)inv_fac[i]=1ll*inv_fac[i-1]*inv[i]%mod;
}
int Binom(int x,int y){
if(y<0||x<y)return 0;
return 1ll*fac[x]*inv_fac[y]%mod*inv_fac[x-y]%mod;
}
void add(int &x,int y){x=(x+y>=mod?x+y-mod:x+y);}
void dec(int &x,int y){x=(x-y<0?x-y+mod:x-y);}
int add(int x){return x>=mod?x-mod:x;}
int dec(int x){return x<0?x+mod:x;}
int ksm(int x,int y){
int re=1;
for(;y;y>>=1){
if(y&1)re=1ll*re*x%mod;
x=1ll*x*x%mod;
}
return re;
}
int main()
{
SieveInit(maxn-10);
FacInit(maxn-10);
int Te;cin>>Te;while(Te--){
int n,m;
cin>>n>>m;
int ans=0;
auto calc=[&](int x,int y){
return Binom(x-1,y-1);
};
auto solve=[&](int d){
if(n%(m/d))return;
int N = n / (m/d);
// printf("solve : %d %d %d %d\n", d, N, calc(N,d), phi[m/d]);
add(ans, 1ll*calc(N, d) * phi[m/d]%mod);
return;
};
for(int i=1;i*i<=m;i++)
if(m%i==0){
solve(i);
if(i*i != n)solve(m/i);
}
int p = (n-1)/2;
dec(ans, 1ll*m * calc(n-p, m) %mod);
if(m%2==1){
if(n&1){
// printf("ans : %d -> ",ans);
add(ans, 1ll*calc(n/2, m/2) * m%mod);
// printf("%d -> ",ans);
add(ans, 1ll*calc(n/2, m/2+1) * m%mod);
// printf("%d -> ",ans);
dec(ans, 1ll*calc(n/2/2, m/2) * m%mod);
// printf("%d -> ",ans);
dec(ans, 1ll*calc(n/2/2, m/2+1) * m%mod);
// printf("%d\n",ans);
}
else{
add(ans, 1ll*calc(n/2, m/2+1) * m%mod);
dec(ans, 1ll*calc(n/2/2, m/2+1) * m%mod);
dec(ans, 1ll*calc(n/2/2, m/2) * m%mod);
}
}else{
if(n%2==0)add(ans, 1ll*calc(n/2, m/2) * (m/2)%mod);
for(int i=0;i<2;i++)
for(int j=0;j<2;j++)
if((n-i-j)%2==0){
add(ans, 1ll*calc((n-i-j)/2,m/2+1) * (m/2)%mod);
if(i)add(ans, 1ll*calc((n-i-j)/2,m/2) * (m/2)%mod);
if(j)add(ans, 1ll*calc((n-i-j)/2,m/2) * (m/2)%mod);
if(i&&j)add(ans, 1ll*calc((n-i-j)/2,m/2-1) * (m/2)%mod);
if(!i && !j){
dec(ans, 2ll*calc((n-i-j)/2/2,m/2+1) * (m/2)%mod);
dec(ans, 2ll*calc((n-i-j)/2/2,m/2) * (m/2)%mod);
}else if(i && j){
dec(ans, 2ll*calc((n-i-j)/2/2,m/2+1) * (m/2)%mod);
dec(ans, 4ll*calc((n-i-j)/2/2,m/2) * (m/2)%mod);
dec(ans, 2ll*calc((n-i-j)/2/2,m/2-1) * (m/2)%mod);
}else{
dec(ans, 1ll*calc((n-i-j)/2/2,m/2+1) * (m/2)%mod); // 1 + n/2 , 0
dec(ans, 1ll*calc((n-i-j)/2/2,m/2) * (m/2)%mod);
dec(ans, 1ll*calc((n-i-j)/2/2,m/2+1) * (m/2)%mod);// 0 + n/2 , 1
dec(ans, 1ll*calc((n-i-j)/2/2,m/2) * (m/2)%mod);
dec(ans, 1ll*calc((n-i-j)/2/2,m/2-1) * (m/2)%mod);
}
}
}
ans=1ll*ans*ksm(2*m,mod-2)%mod;
cout<<ans<<'\n';
}
}
/*
1
7 4
*/
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 217ms
memory: 171988kb
input:
4 3 3 4 3 5 3 7 4
output:
1 0 1 3
result:
ok 4 tokens
Test #2:
score: -100
Wrong Answer
time: 309ms
memory: 172032kb
input:
10000 8708700 6531525 8062080 4031040 7068600 2356200 3659040 332640 7309575 2088450 5503680 1572480 7162848 3581424 9831360 7724640 6306300 5045040 5783400 2891700 4677120 2338560 5110560 786240 9525600 2381400 6955200 4173120 8229375 3291750 7068600 5405400 9639000 3213000 5969040 2984520 5274360 ...
output:
70575804 911063149 736112291 369575992 757290919 136771321 157961376 482306068 808445792 111975446 589376785 548955436 475354332 356837429 8399710 201203710 516058717 699547325 506234162 982243306 632144614 975420242 969330198 969225699 690742488 539447570 315722230 239132520 402932842 865811879 631...
result:
wrong answer 5th words differ - expected: '506078051', found: '757290919'