chore: import upstream snapshot with attribution

math/prime_factorization.cpp

@@ -0,0 +1,78 @@
+/**
+ * @file
+ * @brief Prime factorization of positive integers
+ */
+#include <algorithm>
+#include <cstring>
+#include <iostream>
+#include <vector>
+
+/** Declaring variables for maintaing prime numbers and to check whether a
+ * number is prime or not
+ */
+bool isprime[1000006];
+
+/** list of prime numbers */
+std::vector<int> prime_numbers;
+
+/** list of prime factor-pairs */
+std::vector<std::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(std::make_pair(prime_numbers[i], count));
+    }
+}
+
+/** Main program */
+int main() {
+    int num;
+    std::cout << "\t\tComputes the prime factorization\n\n";
+    std::cout << "Type in a number: ";
+    std::cin >> num;
+
+    SieveOfEratosthenes(num);
+
+    prime_factorization(num);
+
+    // Prime factors with their powers in the given number in new line
+    for (auto it : factors) {
+        std::cout << it.first << " " << it.second << std::endl;
+    }
+
+    return 0;
+}