Flatten the math directory (#657)

math/prime_factorization.cpp

@@ -0,0 +1,81 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+using namespace std;
+
+// Declaring variables for maintaing prime numbers and to check whether a number is prime or not
+bool isprime[1000006];
+vector<int> prime_numbers;
+vector<pair<int, int>> factors;
+
+// Calculating prime number upto a given range
+void SieveOfEratosthenes(int N)
+{
+    // initializes the array isprime
+    memset(isprime, true, sizeof isprime);
+
+    for (int i = 2; i <= N; i++)
+    {
+        if (isprime[i])
+        {
+            for (int j = 2 * i; j <= N; j += i)
+                isprime[j] = false;
+        }
+    }
+
+    for (int i = 2; i <= N; i++)
+    {
+        if (isprime[i])
+            prime_numbers.push_back(i);
+    }
+}
+
+// Prime factorization of a number
+void prime_factorization(int num)
+{
+
+    int number = num;
+
+    for (int i = 0; prime_numbers[i] <= num; i++)
+    {
+        int count = 0;
+
+        // termination condition
+        if (number == 1)
+        {
+            break;
+        }
+
+        while (number % prime_numbers[i] == 0)
+        {
+            count++;
+            number = number / prime_numbers[i];
+        }
+
+        if (count)
+            factors.push_back(make_pair(prime_numbers[i], count));
+    }
+}
+
+/*
+    I added a simple UI.
+*/
+int main()
+{
+    int num;
+    cout << "\t\tComputes the prime factorization\n\n";
+    cout << "Type in a number: ";
+    cin >> num;
+
+    SieveOfEratosthenes(num);
+
+    prime_factorization(num);
+
+    // Prime factors with their powers in the given number in new line
+    for (auto it : factors)
+    {
+        cout << it.first << " " << it.second << endl;
+    }
+
+    return 0;
+}