Prime Factors using C++

C++/Pigeonhole_Sort.cpp

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+/* C program to implement Pigeonhole Sort */
+#include <bits/stdc++.h>
+using namespace std;
+
+/* Sorts the array using pigeonhole algorithm */
+void pigeonholeSort(int arr[], int n)
+{
+	// Find minimum and maximum values in arr[]
+	int min = arr[0], max = arr[0];
+	for (int i = 1; i < n; i++) {
+		if (arr[i] < min)
+			min = arr[i];
+		if (arr[i] > max)
+			max = arr[i];
+	}
+	int range = max - min + 1; // Find range
+
+	// Create an array of vectors. Size of array
+	// range. Each vector represents a hole that
+	// is going to contain matching elements.
+	vector<int> holes[range];
+
+	// Traverse through input array and put every
+	// element in its respective hole
+	for (int i = 0; i < n; i++)
+		holes[arr[i] - min].push_back(arr[i]);
+
+	// Traverse through all holes one by one. For
+	// every hole, take its elements and put in
+	// array.
+	int index = 0; // index in sorted array
+	for (int i = 0; i < range; i++) {
+		vector<int>::iterator it;
+		for (it = holes[i].begin(); it != holes[i].end(); ++it)
+			arr[index++] = *it;
+	}
+}
+
+// Driver program to test the above function
+int main()
+{
+	int arr[] = { 8, 3, 2, 7, 4, 6, 8 };
+	int n = sizeof(arr) / sizeof(arr[0]);
+
+	pigeonholeSort(arr, n);
+
+	printf("Sorted order is : ");
+	for (int i = 0; i < n; i++)
+		printf("%d ", arr[i]);
+
+	return 0;
+}

C++/Primefactor.cpp

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+// C++ program to print all prime factors
+#include <bits/stdc++.h>
+using namespace std;
+
+// A function to print all prime
+// factors of a given number n
+void primeFactors(int n)
+{
+	// Print the number of 2s that divide n
+	while (n % 2 == 0)
+	{
+		cout << 2 << " ";
+		n = n/2;
+	}
+
+	// n must be odd at this point. So we can skip
+	// one element (Note i = i +2)
+	for (int i = 3; i <= sqrt(n); i = i + 2)
+	{
+		// While i divides n, print i and divide n
+		while (n % i == 0)
+		{
+			cout << i << " ";
+			n = n/i;
+		}
+	}
+
+	// This condition is to handle the case when n
+	// is a prime number greater than 2
+	if (n > 2)
+		cout << n << " ";
+}
+
+/* Driver code */
+int main()
+{
+	int n = 315;
+	primeFactors(n);
+	return 0;
+}
+

C++/Radix_sort.cpp

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+// C++ implementation of Radix Sort
+
+#include <iostream>
+using namespace std;
+
+// A utility function to get maximum value in arr[]
+int getMax(int arr[], int n)
+{
+	int mx = arr[0];
+	for (int i = 1; i < n; i++)
+		if (arr[i] > mx)
+			mx = arr[i];
+	return mx;
+}
+
+// A function to do counting sort of arr[] according to
+// the digit represented by exp.
+void countSort(int arr[], int n, int exp)
+{
+	int output[n]; // output array
+	int i, count[10] = { 0 };
+
+	// Store count of occurrences in count[]
+	for (i = 0; i < n; i++)
+		count[(arr[i] / exp) % 10]++;
+
+	// Change count[i] so that count[i] now contains actual
+	// position of this digit in output[]
+	for (i = 1; i < 10; i++)
+		count[i] += count[i - 1];
+
+	// Build the output array
+	for (i = n - 1; i >= 0; i--) {
+		output[count[(arr[i] / exp) % 10] - 1] = arr[i];
+		count[(arr[i] / exp) % 10]--;
+	}
+
+	// Copy the output array to arr[], so that arr[] now
+	// contains sorted numbers according to current digit
+	for (i = 0; i < n; i++)
+		arr[i] = output[i];
+}
+
+// The main function to that sorts arr[] of size n using
+// Radix Sort
+void radixsort(int arr[], int n)
+{
+	// Find the maximum number to know number of digits
+	int m = getMax(arr, n);
+
+	// Do counting sort for every digit. Note that instead
+	// of passing digit number, exp is passed. exp is 10^i
+	// where i is current digit number
+	for (int exp = 1; m / exp > 0; exp *= 10)
+		countSort(arr, n, exp);
+}
+
+// A utility function to print an array
+void print(int arr[], int n)
+{
+	for (int i = 0; i < n; i++)
+		cout << arr[i] << " ";
+}
+
+// Driver Code
+int main()
+{
+	int arr[] = { 170, 45, 75, 90, 802, 24, 2, 66 };
+	int n = sizeof(arr) / sizeof(arr[0]);
+
+	// Function Call
+	radixsort(arr, n);
+	print(arr, n);
+	return 0;
+}