prints out all ways to multiply smaller integers

Posted 2020-10-17 apanda009

Write a program that takes an integer and prints out all ways to multiply smaller integers that equal the original number, 
without repeating sets of factors. In other words, if your output contains 4 * 3, 
you should not print out 3 * 4 again as that would be a repeating set. Note that this is not asking for prime factorization only. 
Also, you can assume that the input integers are reasonable in size; correctness is more important than efficiency. 

Eg: PrintFactors(12) 12 * 1 6 * 2 4 * 3 3 * 2 * 2

 

public class PrintFactors {
	public static void main(String[] args) {
		printFactor(100);
	}

	private static void printFactor(int n) {
		if (n <= 0) {
			System.out.print("Wrong input!");
			return;
		}
		if (n == 1) {
			System.out.print("1");
			return;
		}
		long[] a = new long[n/2];
		findFactor(n/2, n, a, 0);

	}

	private static void findFactor(long i, long n, long[] arr, int index) {
		if (i == 1) {
			if (n == 1) {
				for (int k = 0; k < index - 1; k++) {
					System.out.print(arr[k]);
					if (k < index - 2) {
						System.out.print("*");
					}
				}
				System.out.println();

			}
			return;
		}
		for (long k = i; k >= 1; k--) {
			if (n % k == 0) {
				arr[index] = k;
				findFactor(k, n / k, arr, index + 1);
			}
		}
	}

}