[cpp] 백준 2014 소수의 곱 - Gold I (민코딩 Ugly Number)

seoul_21_minjaekim/BoJ/Gold I/boj2014/README.md

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+# [BoJ 2014 �Ҽ��� ��](https://www.acmicpc.net/problem/2014)
+
+## ī�װ���
+
+����, �ڷ� ����, ������, �켱���� ť
+
+## �ð����⵵
+
+O(n * k)
+
+## �ؼ�
+
+�Է¹��� `k`���� �Ҽ��� �� �Ҽ��� ����Ű�� �ε����� �����ϴ� `prime_numbers` �迭�� �����Ѵ�.
+
+```cpp
+
+```cpp
+int k, n;
+cin >> k >> n;
+
+pair<int, int> prime_numbers[100];
+for (int i = 0; i < k; ++i) {
+    cin >> prime_numbers[i].first;
+    prime_numbers[i].second = 0;
+}
+```
+
+�Ҽ��� ��(`ugly number`)�� �����ϴ� �迭�� �����Ѵ�.
+�Ҽ��� ���ذ��� ������ ���ڰ� �ʿ��ϱ� ������ 1�� �ϳ� �־��ش�.
+
+```cpp
+int ugly_numbers[100001] = { 1 };
+```
+
+�� �Ҽ��� �����͸� ����Ű�� `prime_numbers` �迭�� �̿��� ugly number�� ���ϰ�, �� �� �ּҰ��� `ugly_numbers` �迭�� �ִ´�.
+�� �� �ش� `ugly number`�� ���� �� �ִ� �Ҽ����� �����͸� ������Ų��.
+
+```cpp
+for (int i = 1; i < n + 1; ++i)
+{
+    int min_number = numeric_limits<int>::max();
+    int min_index[100];
+    int min_count = 0;
+    for (int j = 0; j < k; ++j)
+    {
+        int next_number = prime_numbers[j].first * ugly_numbers[prime_numbers[j].second];
+        if (next_number < min_number)
+        {
+            min_number = prime_numbers[j].first * ugly_numbers[prime_numbers[j].second];
+            min_index[0] = j;
+            min_count = 1;
+        }
+        else if (next_number == min_number)
+        {
+            min_index[min_count] = j;
+            ++min_count;
+        }
+    }
+    ugly_numbers[i] = min_number;
+    for (int j = 0; j < min_count; ++j)
+        ++prime_numbers[min_index[j]].second;
+}
+```
+
+## ���� ���
+
+�޸�: 2292 KB, �ð�: 12 ms
+
+��� : [�¾ҽ��ϴ�!!](http://boj.kr/ce23d5163b5948499f4ff2d1031287b9)

seoul_21_minjaekim/BoJ/Gold I/boj2014/boj2014.cpp

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+#include <iostream>
+#include <limits>
+
+using namespace std;
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+    cout.tie(nullptr);
+
+
+    int k, n;
+    cin >> k >> n;
+
+    pair<int, int> prime_numbers[100];
+    for (int i = 0; i < k; ++i) {
+        cin >> prime_numbers[i].first;
+        prime_numbers[i].second = 0;
+    }
+    int ugly_numbers[100001] = { 1 };
+
+    for (int i = 1; i < n + 1; ++i)
+    {
+        int min_number = numeric_limits<int>::max();
+        int min_index[100];
+        int min_count = 0;
+        for (int j = 0; j < k; ++j)
+        {
+            int next_number = prime_numbers[j].first * ugly_numbers[prime_numbers[j].second];
+            if (next_number < min_number)
+            {
+                min_number = prime_numbers[j].first * ugly_numbers[prime_numbers[j].second];
+                min_index[0] = j;
+                min_count = 1;
+            }
+            else if (next_number == min_number)
+            {
+                min_index[min_count] = j;
+                ++min_count;
+            }
+        }
+        ugly_numbers[i] = min_number;
+        for (int j = 0; j < min_count; ++j)
+            ++prime_numbers[min_index[j]].second;
+    }
+
+    cout << ugly_numbers[n] << endl;
+
+    return 0;
+}