Here is source code of the C++ Program to demonstrate the Generation of All Unique Partitions of an Integer. The C++ program is successfully compiled and run on a Linux system. The program output is also shown below.
/*
* C++ Program to Generate All Unique Partitions of an Integer
*/
#include<iostream>
using namespace std;
/*
* print an array p[] of size 'n'
*/
void printArray(int p[], int n)
{
for (int i = 0; i < n; i++)
cout << p[i] << " ";
cout << endl;
}
void printAllUniqueParts(int n)
{
int p[n]; // An array to store a partition
int k = 0; // Index of last element in a partition
p[k] = n; // Initialize first partition as number itself
// This loop first prints the current partition then generates the next partition.
// The loop stops when the current partition has all 1s
while (true)
{
// print current partition
printArray(p, k + 1);
// Find the rightmost non-one value in p[]. Also, update the rem_val
// So that we know how much value can be accommodated
int rem_val = 0;
while (k >= 0 && p[k] == 1)
{
rem_val += p[k];
k--;
}
// if k < 0, all the values are 1 so there are no more partitions
if (k < 0)
return;
// Decrease the p[k] found above and adjust the rem_val
p[k]--;
rem_val++;
// If rem_val is more, then the sorted order is violeted.
// Divide rem_val in differnt values of size p[k]
// Copy these values at different positions after p[k]
while (rem_val > p[k])
{
p[k+1] = p[k];
rem_val = rem_val - p[k];
k++;
}
// Copy rem_val to next position and increment position
p[k+1] = rem_val;
k++;
}
}
/*
* Main
*/
int main()
{
int value;
while(1)
{
cout<<"Enter an Integer(0 to exit): ";
cin>>value;
if (value == 0)
break;
cout << "All Unique Partitions of "<<value<<endl;
printAllUniqueParts(value);
cout<<endl;
}
return 0;
}
$ g++ unique_partitions.cpp $ a.out Enter an Integer(0 to exit): 2 All Unique Partitions of 2 2 1 1 Enter an Integer(0 to exit): 3 All Unique Partitions of 3 3 2 1 1 1 1 Enter an Integer(0 to exit): 4 All Unique Partitions of 4 4 3 1 2 2 2 1 1 1 1 1 1 Enter an Integer(0 to exit): 5 All Unique Partitions of 5 5 4 1 3 2 3 1 1 2 2 1 2 1 1 1 1 1 1 1 1 Enter an Integer(0 to exit): 7 All Unique Partitions of 7 7 6 1 5 2 5 1 1 4 3 4 2 1 4 1 1 1 3 3 1 3 2 2 3 2 1 1 3 1 1 1 1 2 2 2 1 2 2 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 Enter an Integer(0 to exit): 0 ------------------ (program exited with code: 1) Press return to continue