백준 2312번 수 복원하기

문제 링크입니다: https://www.acmicpc.net/problem/2312

에라토스테네스의 체를 이용하면 쉽게 풀 수 있는 문제였습니다.

#include <iostream>

#include <vector>

using namespace std;

 

const int MAX = 100000 + 1;

 

int minFactor[MAX];

vector<int> prime;

 

void eratosthenes(void)

{

        minFactor[0] = minFactor[1] = -1;

        for (int i = 2; i < MAX; i++)

                 minFactor[i] = i;

 

        for (int i = 2; i*i < MAX; i++)

                 if (minFactor[i] == i)

                         for (int j = i * i; j < MAX; j += i)

                                 if (minFactor[j] == j)

                                          minFactor[j] == i;

 

        for (int i = 2; i < MAX; i++)

                 if (minFactor[i] == i)

                         prime.push_back(i);

}

 

int main(void)

{

        ios_base::sync_with_stdio(0);

        cin.tie(0);

        int T;

        cin >> T;

 

        eratosthenes();

        for (int t = 0; t < T; t++)

        {

                 int N;

                 cin >> N;

 

                 for (int i = 0; i < prime.size(); i++)

                 {

                         int cnt = 0;

                         while (!(N%prime[i]))

                         {

                                 cnt++;

                                 N /= prime[i];

                                 if (N == 1)

                                          break;

                         }

                         if(cnt)

                                 cout << prime[i] << " " << cnt << "\n";

                         if (N == 1)

                                 break;

                 }

        }

        return 0;

}

개발환경:Visual Studio 2017

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