답안 #474770

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
474770 2021-09-19T16:02:50 Z egod1537 팔찌 (kriii4_V) C++14
6 / 100
1000 ms 31828 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 += phi[n / i] * pwk[i];
			if (n / i != i) ans += phi[n / (n / i)] * pwk[n / i];
		}
	}
	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 146 ms 31724 KB Output is correct
2 Correct 147 ms 31680 KB Output is correct
3 Correct 147 ms 31620 KB Output is correct
4 Correct 144 ms 31692 KB Output is correct
5 Correct 146 ms 31680 KB Output is correct
6 Correct 149 ms 31612 KB Output is correct
7 Correct 144 ms 31700 KB Output is correct
8 Correct 143 ms 31680 KB Output is correct
9 Correct 148 ms 31700 KB Output is correct
10 Correct 148 ms 31776 KB Output is correct
11 Correct 143 ms 31684 KB Output is correct
12 Correct 146 ms 31688 KB Output is correct
13 Correct 144 ms 31764 KB Output is correct
14 Correct 149 ms 31808 KB Output is correct
15 Correct 148 ms 31688 KB Output is correct
16 Correct 147 ms 31688 KB Output is correct
17 Correct 153 ms 31684 KB Output is correct
18 Correct 143 ms 31640 KB Output is correct
19 Correct 155 ms 31688 KB Output is correct
20 Correct 150 ms 31692 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 144 ms 31828 KB Output is correct
2 Correct 149 ms 31688 KB Output is correct
3 Correct 149 ms 31720 KB Output is correct
4 Correct 218 ms 31724 KB Output is correct
5 Execution timed out 1088 ms 31684 KB Time limit exceeded
6 Halted 0 ms 0 KB -