oj.uz

답안 #19920

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
19920 2016-02-25T07:16:30 Z cki86201 팔찌 (kriii4_V) C++14
100 / 100
 384 ms 25160 KB 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <math.h>
#include <assert.h>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <string>
#include <algorithm>
#include <iostream>
#include <functional>
#include <unordered_map>
#include <unordered_set>

using namespace std;
typedef long long ll;
typedef pair<int, int> Pi;
#define Fi first
#define Se second
#define pb(x) push_back(x)
#define sz(x) (int)x.size()
#define rep(i,n) for(int i=0;i<n;i++)
#define all(x) x.begin(),x.end()

const ll MOD = 1e9 + 7;

ll pw(ll x, ll y){
	ll res = 1;
	while(y){
		if(y & 1)res = res * x % MOD;
		x = x * x % MOD;
		y >>= 1;
	}
	return res;
}

ll pwk[1000010];
int phi[1000010];
int isp[1000010];
ll sum[1000010];

int main(){
	int N, K;
	scanf("%d%d", &N, &K);
	//N = K = 1000000;
	pwk[0] = 1;
	for(int i=1;i<1000010;i++)pwk[i] = K * pwk[i-1] % MOD;
	phi[1] = 1;
	for(int i=2;i<1000010;i++)phi[i] = i, isp[i] = 1;
	for(int i=2;i<1000010;i++){
		if(isp[i]){
			phi[i] = i-1;
			for(int j=i+i;j<1000010;j+=i){
				isp[j] = 0;
				phi[j] /= i;
				phi[j] *= (i-1);
			}
		}
	}
	ll ans = 1;
	ll p2 = pw(2, MOD-2);
	ll p4 = pw(4, MOD-2);
	for(int i=1;i<=N;i++){
		for(int j=i,t=1;j<=N;j+=i,t++){
			sum[j] += phi[i] * pwk[t];
			sum[j] %= MOD;
		}
	}
	for(int i=1;i<=N;i++){
		//printf("%d %lld\n", i, sum);
		ans += sum[i] * pw(2*i, MOD-2);
		if(i & 1)ans += p2 * pwk[(i+1)/2];
		else ans += p4 * (K+1) % MOD * pwk[i/2];
		ans %= MOD;
	}
	printf("%lld", ans);
	//printf("\n%d", clock());
	return 0;
}

Subtask #1
6.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 46 ms 25160 KB Output is correct
2 Correct 46 ms 25160 KB Output is correct
3 Correct 50 ms 25160 KB Output is correct
4 Correct 42 ms 25160 KB Output is correct
5 Correct 50 ms 25160 KB Output is correct
6 Correct 46 ms 25160 KB Output is correct
7 Correct 46 ms 25160 KB Output is correct
8 Correct 46 ms 25160 KB Output is correct
9 Correct 50 ms 25160 KB Output is correct
10 Correct 42 ms 25160 KB Output is correct
11 Correct 50 ms 25160 KB Output is correct
12 Correct 46 ms 25160 KB Output is correct
13 Correct 51 ms 25160 KB Output is correct
14 Correct 49 ms 25160 KB Output is correct
15 Correct 45 ms 25160 KB Output is correct
16 Correct 49 ms 25160 KB Output is correct
17 Correct 49 ms 25160 KB Output is correct
18 Correct 50 ms 25160 KB Output is correct
19 Correct 49 ms 25160 KB Output is correct
20 Correct 46 ms 25160 KB Output is correct

Subtask #2
94.0 / 94.0

# 결과 실행 시간 메모리 Grader output
1 Correct 50 ms 25160 KB Output is correct
2 Correct 50 ms 25160 KB Output is correct
3 Correct 46 ms 25160 KB Output is correct
4 Correct 59 ms 25160 KB Output is correct
5 Correct 250 ms 25160 KB Output is correct
6 Correct 297 ms 25160 KB Output is correct
7 Correct 246 ms 25160 KB Output is correct
8 Correct 283 ms 25160 KB Output is correct
9 Correct 319 ms 25160 KB Output is correct
10 Correct 368 ms 25160 KB Output is correct
11 Correct 321 ms 25160 KB Output is correct
12 Correct 354 ms 25160 KB Output is correct
13 Correct 226 ms 25160 KB Output is correct
14 Correct 347 ms 25160 KB Output is correct
15 Correct 215 ms 25160 KB Output is correct
16 Correct 256 ms 25160 KB Output is correct
17 Correct 382 ms 25160 KB Output is correct
18 Correct 240 ms 25160 KB Output is correct
19 Correct 288 ms 25160 KB Output is correct
20 Correct 384 ms 25160 KB Output is correct