CareerCup

static void printDivisors(int n){
		System.out.println("1*" + n);
		printDivisors("",1,n);
	}
	
	static void printDivisors(String prefix,int prev,int n){
		if(n<2)
			return;
		int s = (int) Math.ceil(Math.sqrt(n));
		for(int i = 2;i<=s;i++){
			if(n%i == 0){
				if(i>=prev && n/i>=i){
					System.out.println(prefix + i + "*" + n/i);
					printDivisors(prefix + i + "*",i,n/i);
				}
			}
				
		}
	}

If you are including 1 then 1*2*6 can also be one solution..

for(int i = 2;i<s;i++) should be for(int i = 2;i<=s;i++)

Find all the prime factors of the number.
We can express the number as product of its prime factors.

#include<iostream>
#include<conio.h>
#include<math.h>
using namespace std;

int main() {
double num;
cin >> num;
for(int i=1;i<=sqrt(num);i++) {
if((int)num%i==0)
cout << i << " * " << num/i << endl;

}
getch();
return 0;
}

What about this one? Let me know if I have made any mistakes

public static void printDivisors(int n){
		int m=0;
		HashMap<Integer, Integer> ab=new HashMap<Integer, Integer>();
		while(m<n/2){
		    m++;
		    if(n%m==0){
		    	if(!ab.containsKey(n/m)){
		    		ab.put(m, n/m);
		    	}
		    }
		    	
		}
		Iterator x=ab.entrySet().iterator();
		while(x.hasNext()){
			Map.Entry numbers=(Map.Entry)x.next();
			System.out.println(numbers.getKey());
			System.out.println(numbers.getValue());
			
		}
	}

import java.util.*;
import java.lang.*;

class Main{

	public static void main (String[] args){
		printFactors(12);
	}

	public static void printFactors(int n){
		for(int i = 1; i <= Math.sqrt(n); i++){
			if(n % i == 0){
				System.out.println(""+(n/i)+"*"+i);
			}
		}
	}
}

I know I am excluding the 1*n case, but that is trivial

vector < string> print_all_factorizations(int number)
{
	vector<string> result ;
	int j =number;
	for(int i =1; i < j; i++)
	{
		if(number % i == 0)
		{
			j=number/i;
			//cout << i << "*" << j << endl;
			char buff[512];
			sprintf(buff, "%i*%i",i,j);
			result.push_back(buff);
			
			if(j != number)
			{
				vector<string> subcall = print_all_factorizations(j);
				for(int s =0; s < subcall.length; s++)
				{
					sprintf(buff, "%i*%i",i,subcall[s].c_str());
					result.push_back(buff);

				}
			}
		}
	}
	return result;
}

sorry, small correction

vector < string> print_all_factorizations(int number)
{
	vector<string> result ;
	int j =number;
	for(int i =2; i < j; i++)
	{
		if(number % i == 0)
		{
			j=number/i;
			//cout << i << "*" << j << endl;
			char buff[512];
			sprintf(buff, "%d*%d",i,j);
			result.push_back(buff);
			
			if(j != number)
			{
				vector<string> subcall = print_all_factorizations(j);
				for(int s =0; s < subcall.size(); s++)
				{
					sprintf(buff, "%d*%s",i,subcall[s].c_str());
					result.push_back(buff);

				}
			}
		}
	}
	return result;
}

vector<vector<int>>factors(int num)
{
vector<vector<int>> result;

if(num==1)
{
result.push_back({1});
return result;
}

result.push_back({1,num});


for(int i =2; i< num;i++)
{
if(num%i==0)
{
int rest = num/i;
if(rest>=i)
{
//result.push_back(i,rest);

vector<vector<int>> restresult = factors(rest);

for(auto& item: restresult)
{
if(item[0]==1)
{
item[0]= i;
result.push_back(item);
}
else
{
if(i<= item[0])
{
item.insert(item.begin(),i);
result.push_back(item);
}

}

}


}
else
break;


}


}


}

vector<vector<int>>factors(int num)
{
	vector<vector<int>> result;

	if(num==1)
	{
		result.push_back({1});
		return result;
	}

	result.push_back({1,num});


	for(int i =2; i< num;i++)
	{
		if(num%i==0)
		{
			int rest = num/i;
			if(rest>=i)
			{
				//result.push_back(i,rest);
				
				vector<vector<int>> restresult = factors(rest);

				for(auto& item: restresult)
				{
					if(item[0]==1)
					{
						item[0]= i;
						result.push_back(item);
					}
					else
					{
						if(i<= item[0])
						{
							item.insert(item.begin(),i);
							result.push_back(item);
						}

					}
					
				}


			}
			else
				break;


   		}
		

	}
	

}

vector<vector<int>>factors(int num)
{
	vector<vector<int>> result;

	if(num==1)
	{
		result.push_back({1});
		return result;
	}

	result.push_back({1,num});


	for(int i =2; i< num;i++)
	{
		if(num%i==0)
		{
			int rest = num/i;
			if(rest>=i)
			{
				//result.push_back(i,rest);
				
				vector<vector<int>> restresult = factors(rest);

				for(auto& item: restresult)
				{
					if(item[0]==1)
					{
						item[0]= i;
						result.push_back(item);
					}
					else
					{
						if(i<= item[0])
						{
							item.insert(item.begin(),i);
							result.push_back(item);
						}

					}
					
				}


			}
			else
				break;


   		}
		

	}
	

}

}

Simple recursive approach

void subset_product(vector<int> nums, int target, int product, vector<int> &temp, int pos) {
	if(target == product) {
		result.push_back(temp);
		return;
	}
	if(pos >= nums.size() || product > target)
		return;

	for(int i=pos; i<nums.size(); i++) {
		temp.push_back(nums[i]);
		subset_product(nums, target, product * nums[i], temp, i);
		temp.pop_back();
	}

	
}

int main() {
	
	int arr[] = {2,3,4,5,6,7,8,9,10,11,12};

	vector<int> nums (arr, arr + sizeof(arr)/sizeof(arr[0])) ;

	vector<int> temp;
	subset_product(nums, 12, 1, temp, 0);

	return 0;
}