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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#180452#7087. Counting Polygonsbrz#WA 257ms172228kbC++203.3kb2023-09-15 20:57:082023-09-15 20:57:09

Judging History

你现在查看的是最新测评结果

  • [2023-09-15 20:57:09]
  • 评测
  • 测评结果:WA
  • 用时:257ms
  • 内存:172228kb
  • [2023-09-15 20:57:08]
  • 提交

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, 2ll*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: 192ms
memory: 172156kb

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: 257ms
memory: 172228kb

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
471556430
156021347
757290919
481154211
157961376
482306068
808445792
111975446
589376785
352589541
251428644
356837429
8399710
201203710
726347943
699547325
759787154
982243306
632144614
975420242
856110813
192083559
690742488
539447570
352112592
239132520
402932842
865811879
220...

result:

wrong answer 3rd words differ - expected: '736112291', found: '471556430'