Submission #9136

#	Time	Username	Problem	Language	Result	Execution time	Memory
9136		ainta	Actual visible points (kriii2_AC)	C++98	0 / 4	192 ms	6292 KiB

AC

#pragma warning(disable:4996)
#include<stdio.h>
#include<algorithm>
using namespace std;
int n, m, w[101000];
long long Mod = 1000000007, F[201000], G[201000], Res, invF[201000];
bool chk[101000];
long long Inv(long long a){
	long long cnt = Mod - 2, r = 1;
	while (cnt){
		if (cnt % 2){
			r = r*a%Mod;
		}
		cnt /= 2;
		a = a*a%Mod;
	}
	return r;
}
long long Gap(int a){
	if (a == 0)return 0;
	return F[a + n - 1] * invF[n] % Mod * invF[a - 1] % Mod;
}
void Do(int a){
	G[a] = (G[a] + Gap(a) - Gap(a-1) + Mod) % Mod;
	int i, ck = chk[a];
	for (i = a * 2; i <= 100000; i += a){
		G[i] = (G[i] + Mod - G[a]) % Mod;
		if (chk[i])ck = true;
	}
	if (ck)Res = (Res + G[a]) % Mod;
}
int main()
{
	int i;
	scanf("%d%d", &n, &m);
	for (i = 1; i <= m; i++){
		scanf("%d", &w[i]);
		chk[w[i]] = true;
	}
	F[0] = 1;
	for (i = 1; i <= 200010; i++){
		F[i] = F[i - 1] * i%Mod;
		invF[i] = Inv(F[i]);
	}
	for (i = 1; i <= 100000; i++){
		Do(i);
	}
	printf("%lld\n", Res);
}

• Subtask 1: 0 / 1
• Subtask 2: 0 / 3