An old question: Divide positive integer N into the sum of several num different positive integers

/*

Http://www.newsmth.net/bbstcon.php? Board = Algorithm & gid = 33809

Sender: firebugp (Firefox), email area: Algorithm
Question: an old question
Mail station: Shui muCommunity(Tue Nov 3 00:50:48 2009), Station

Divide positive integer N into the sum of several num different positive integers and give all possible split results (numbers are the same and order is different
For example, 6 = 1 + 2 + 3 and 6 = 3 + 2 + 1 are the same thing, 6 = 2 + 4 and 6 = 1 + 5 are eligible
Results)
*/

# Include <stdio. h>
# Include <set>
# Include <vector>
# Include <algorithm>

Typedef STD: Set <int> container;
Container res;
STD: vector <container> allres;

Void printall ()
{
For (INT I = 0; I <allres. Size (); I ++)
{
For (container: iterator it = allres [I]. Begin (), end = allres [I]. End ();
It! = End; ++ it)
{
Printf ("% d", * it );
}
Printf ("\ n ");
}
}

Bool operator = (container const & A, container const & B)
{
If (A. Size ()! = B. Size ())
Return false;

For (container: const_iterator ita = A. Begin (), Enda = A. End (), ITB = B. Begin ();
Ita! = ENDA; ++ ITA, ++ ITB)
{
If (* ita! = * ITB) return false;
}

Return true;
}

Void add ()
{
If (allres. End ()! = STD: Find (allres. Begin (), allres. End (), Res ))
Return;
Allres. push_back (RES );
}

// divide positive integer N into the sum of different positive integers of num
// place the result in the global variable allres
void split (int n, int num)
{< br> If (Num * (Num + 1)/2> N) // no solution
return;
// there is only one number, ending
If (num = 1)
{< br> If (res. find (n) = res. end ()
{< br> res. insert (n);
Add ();
res. erase (n);
}< br> return;
}

// Otherwise, traverse all possible
For (INT I = 1; I <= N-(num-1) * num/2; I ++)
{
If (res. Find (I) = res. End ())
{
Res. insert (I );
// If (n-I >=( num-1) * num/2)
Split (n-I, num-1 );
Res. Erase (I );
}
}
}

Void main ()
{
Split (16, 3 );
Printall ();
}