Permutation of a vector

**tallgeese84** · 03-28-2005

I was hoping for a little help on this subject. I am trying to find all the permutations of a vector. Ive done a bit of research and could only find a recursive solution. Recursion still kind of confuses me, so I was wondering if anyone could help with a non recursive version? Heres what I have so far:

Code:

void perm(vector<int>v, int num, int curNum, int posNum, int &output)
{
	v.insert(v.begin()+posNum, curNum);//puts the current number into the desired position
	
	if(curNum == num)//stop case
	{
		print(v, num, output);//print function
		return;
	}

	for(int i=0; i <= curNum; i++)
	{
		perm(v, num, curNum+1, i, output);//recursive call
	}
}

**treenef** · 03-29-2005

What exactly do you mean by finding all permutations of a vector?
Explain

**misplaced** · 03-29-2005

this is the perfect chance to learn about recursion.
make this modification:

Code:

void perm(vector<int>v, int num, int curNum, int posNum, int &output, int level)
{
	v.insert(v.begin()+posNum, curNum);//puts the current number into the desired position

	if(curNum == num)//stop case
	{
		print(v, num, output, level);//print function
		return;
	}

	for(int i=0; i <= curNum; i++)
	{
		perm(v, num, curNum+1, i, output, level++);//recursive call
	}
}

**hk_mp5kpdw** · 03-29-2005

Code:

#include <algorithm>
#include <vector>

...

std::vector<int> intVect;

...

std::sort(intVect.begin(),intVect.end());
print(...);      // Call your print function
while( std::next_permutation(intVect.begin(), intVect.end()) )
    print(...);  // Call your print function

**tallgeese84** · 03-29-2005

Thanks for the help everyone. This has helped me greatly.

Thread: Permutation of a vector

Thread Tools

Search Thread

Display

Permutation of a vector

Similar Threads

can some one please tell me the cause of the error ?

syntax help?

Vector class

Need some help/advise for Public/Private classes

Certain functions