Submission #342320

#	Time	Username	Problem	Language	Result	Execution time	Memory
342320		VodkaInTheJar	Sažetak (COCI17_sazetak)	C++14	16 / 160	1 ms	384 KiB

sazetak

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#define endl '\n'

using namespace std;

const int maxn = 5e6 + 3; 
const int maxm = 13;

int n, m; 
int k[maxm];
void read()
{
	cin >> n >> m;
	for (int i = 1; i <= m; i++)
	cin >> k[i];
}

pair <long long, long long> extended_euclid(int a, int b)
{
	if (b == 0)
	return {1, 0};
	
	int r = a % b, q = a / b; 
	auto res = extended_euclid(b, r);
	
	return {res.second, res.first - 1ll * res.second * q};
}

bool dp[maxn];
void solve()
{
	int ans = 0;
	for (int i = 1; i <= m; i++)
	if ((n - 1) % k[i] == 0)
	{
		ans++;
		break;
	}
	
	set <long long> s;
	for (int i = 1; i <= m; i++)
	for (int j = 1; j <= m; j++)
	if (__gcd(k[i], k[j]) == 1)
	{
		long long period = 1ll * k[i] * k[j];
		auto sol = extended_euclid(k[j], k[i]);
		
		long long num = sol.second * k[i];
		num %= period;
		if (num < 0)
		num += period;
		
		if (num > n-2)
		continue;
		
		ans += 1 + (n-2-num) / period; 
		
		//for (long long t = num; t <= n-2; t += period)
		//s.insert(t); 
	}
	
	cout << ans + (int)s.size() << endl; 
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);

	read();
	solve();
}

• Subtask 1: 16 / 160