답안 #474771

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
474771 2021-09-19T16:03:36 Z egod1537 팔찌 (kriii4_V) C++14
6 / 100
1000 ms 31816 KB
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

#include<bits/stdc++.h>
#include <unordered_map>

using namespace std;

typedef long long ll;
const ll mod = 1e9 + 7;
typedef pair<ll, ll> pi;
#define var first
#define cnt second

ll pwk[2000001], phi[1000001], low[1000001];
bitset<1000001> vit;
vector<ll> prime;

ll pow(ll x, ll p) {
	ll ret = 1, piv = x % mod;
	while (p) {
		if (p & 1) ret *= piv;
		piv *= piv;
		ret %= mod;
		piv %= mod;
		p >>= 1;
	}
	return ret;
}
ll revmod(ll x) { return pow(x, mod - 2) % mod; }
ll r2;
ll func(ll n, ll k) {
	ll ans = 0;
	for (int i = 1; i * i <= n; i++) {
		if (n % i == 0) {
			ans = (ans + phi[n / i] * pwk[i])%mod;
			if (n / i != i) ans = (ans + phi[n / (n / i)] * pwk[n / i])%mod;
		}
	}
	if (n % 2) ans = (ans + (n * pwk[n / 2 + 1]) % mod) % mod;
	else {
		ll pw = (pwk[n / 2] + pwk[n / 2 + 1]) % mod;
		ans = (ans + (((n * pw) % mod) * r2) % mod) % mod;
	}

	return (ans * revmod(2 * n)) % mod;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);

	phi[1] = 1;
	for (int i = 2; i <= 1000000; i++) {
		if (!vit[i]) 
			for (int j = i; j <= 1000000; j += i) {
				if (!low[j])low[j] = i;
				vit[j] = true;
			}
		phi[i] = i;
		for (int j = i; j != 1;) {
			ll p = low[j];
			while (j % p == 0) j /= p;
			phi[i] = (phi[i] * (p - 1)) / p;
		}
	}

	ll n, k; cin >> n >> k;

	pwk[0] = 1;
	for (int i = 1; i <= 2000000; i++) pwk[i] = (pwk[i - 1] * k) % mod;
	r2 = revmod(2);

	ll ans = 1;
	for (int i = 1; i <= n; i++) ans = (ans + func(i, k)) % mod;
	cout << ans;

	return 0;
}
# 결과 실행 시간 메모리 Grader output
1 Correct 148 ms 31732 KB Output is correct
2 Correct 148 ms 31628 KB Output is correct
3 Correct 146 ms 31680 KB Output is correct
4 Correct 143 ms 31616 KB Output is correct
5 Correct 145 ms 31816 KB Output is correct
6 Correct 149 ms 31696 KB Output is correct
7 Correct 147 ms 31668 KB Output is correct
8 Correct 146 ms 31684 KB Output is correct
9 Correct 148 ms 31708 KB Output is correct
10 Correct 149 ms 31652 KB Output is correct
11 Correct 150 ms 31628 KB Output is correct
12 Correct 145 ms 31684 KB Output is correct
13 Correct 145 ms 31720 KB Output is correct
14 Correct 147 ms 31692 KB Output is correct
15 Correct 147 ms 31680 KB Output is correct
16 Correct 146 ms 31648 KB Output is correct
17 Correct 151 ms 31724 KB Output is correct
18 Correct 147 ms 31636 KB Output is correct
19 Correct 148 ms 31632 KB Output is correct
20 Correct 143 ms 31644 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 152 ms 31672 KB Output is correct
2 Correct 146 ms 31692 KB Output is correct
3 Correct 146 ms 31684 KB Output is correct
4 Correct 226 ms 31728 KB Output is correct
5 Execution timed out 1081 ms 31704 KB Time limit exceeded
6 Halted 0 ms 0 KB -