답안 #20113

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
20113 2016-02-25T16:15:08 Z gs14004 팔찌 (kriii4_V) C++14
100 / 100
567 ms 25160 KB
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <limits.h>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <string>
#include <functional>
#include <vector>
#include <numeric>
#include <deque>
#include <utility>
#include <bitset>
#include <iostream>
using namespace std;
typedef long long lint;
typedef long double llf;
typedef pair<int, int> pi;
const int mod = 1e9 + 7;

lint ipow(lint x, lint p){
    lint ret = 1, piv = x % mod;
    while(p){
        if(p&1) ret *= piv;
        piv *= piv;
        ret %= mod;
        piv %= mod;
        p >>= 1;
    }
    return ret;
}

int low[1000005], phi[1000005];
lint kpow[1000005], inv[1000005];
int n, k;

int main(){
	cin >> n >> k;
	phi[1] = 1;
	for(int i=2; i<=n; i++){
		for(int j=i; j<=n; j+=i){
			if(!low[j]) low[j] = i;
		}
		phi[i] = i;
		for(int j=i; j!=1; ){
			int p = low[j];
			while(j % p == 0){
				j /= p;
			}
			phi[i] = (1ll * phi[i] * (p-1)) / p;
		}
	}
	kpow[0] = 1;
	for(int i=1; i<=n; i++){
		kpow[i] = kpow[i-1] * k % mod;
		inv[i] = ipow(i, mod-2);
	}
	lint ret = 2;
	for(int i=1; i<=n; i++){
		for(int j=i; j<=n; j+=i){
			lint tmp = kpow[i] * phi[j/i] % mod;
			tmp *= inv[j];
			tmp %= mod;
			ret += tmp;
		}
	}
	for(int i=1; i<=n; i++){
		if(i%2 == 0) ret += (1ll * (k+1) * kpow[i/2] % mod) * ((mod + 1) / 2) % mod;
		else ret += kpow[i/2+1];
		ret %= mod;
	}
	ret *= (mod + 1) / 2;
	ret %= mod;
	cout << ret;
}
# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 25160 KB Output is correct
2 Correct 0 ms 25160 KB Output is correct
3 Correct 0 ms 25160 KB Output is correct
4 Correct 0 ms 25160 KB Output is correct
5 Correct 0 ms 25160 KB Output is correct
6 Correct 1 ms 25160 KB Output is correct
7 Correct 0 ms 25160 KB Output is correct
8 Correct 0 ms 25160 KB Output is correct
9 Correct 0 ms 25160 KB Output is correct
10 Correct 0 ms 25160 KB Output is correct
11 Correct 0 ms 25160 KB Output is correct
12 Correct 0 ms 25160 KB Output is correct
13 Correct 0 ms 25160 KB Output is correct
14 Correct 0 ms 25160 KB Output is correct
15 Correct 0 ms 25160 KB Output is correct
16 Correct 0 ms 25160 KB Output is correct
17 Correct 0 ms 25160 KB Output is correct
18 Correct 0 ms 25160 KB Output is correct
19 Correct 0 ms 25160 KB Output is correct
20 Correct 0 ms 25160 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 25160 KB Output is correct
2 Correct 0 ms 25160 KB Output is correct
3 Correct 0 ms 25160 KB Output is correct
4 Correct 29 ms 25160 KB Output is correct
5 Correct 348 ms 25160 KB Output is correct
6 Correct 427 ms 25160 KB Output is correct
7 Correct 326 ms 25160 KB Output is correct
8 Correct 407 ms 25160 KB Output is correct
9 Correct 461 ms 25160 KB Output is correct
10 Correct 546 ms 25160 KB Output is correct
11 Correct 468 ms 25160 KB Output is correct
12 Correct 527 ms 25160 KB Output is correct
13 Correct 313 ms 25160 KB Output is correct
14 Correct 505 ms 25160 KB Output is correct
15 Correct 294 ms 25160 KB Output is correct
16 Correct 347 ms 25160 KB Output is correct
17 Correct 561 ms 25160 KB Output is correct
18 Correct 326 ms 25160 KB Output is correct
19 Correct 399 ms 25160 KB Output is correct
20 Correct 567 ms 25160 KB Output is correct