Check if an number is an permutation

[Safari]

Hi! I'm using this code to see if a number is an permutation of an vector. But it doesn't work as I wish it would. Also, how can I make the code shorter and more efficient?

[syntax="cpp"]bool isPermutation(int tal, vector <int> vektor ){
vector <int> temp = tillVektor(tal);
int * vektorn = new int[temp.size()];
std::copy(temp.begin(),temp.end(),vektorn);
int * vektor1 = new int[vektor.size()];
std::copy(vektor.begin(),vektor.end(),vektor1);
int * vektor2 = new int[vektor.size()];
std::copy(vektor.begin(),vektor.end(),vektor2);

while (next_permutation(vektor2, vektor2 + vektor.size())){
bool sant = true;
for (int i = 0; i < temp.size(); i++)
if (vektor2[i] != vektorn[i])
sant = false;
if (sant) return true;
}

while (prev_permutation(vektor1, vektor1 + vektor.size())){
bool sant = true;
for (int i = 0; i < temp.size(); i++)
if (vektor1[i] != vektorn[i])
sant = false;
if (sant) return true;
}
return false;
}[/syntax]

Thank you in advance.

[Alvaro]

How can a number be a permutation of a vector? A permutation of a vector is another vector.

[Blueteeth]

I assume you convert the int to vector with each element containing 1 digit of the number , am i right ?
That should be easy with O(n^2) algorithm ! .

[Bugdude]

Here's some food for thought: for one vector to be a permutation of another, they only have to have the same size and the same elements (but in any order).

If you think about those two criteria I'm sure you can come up with a better algorithm.

[Safari]

Blueteeth: Yes the function tillVektor(int) converts int to vector. I have no clue what the O(n^2) algorithm is.

However I solved it.

[syntax="cpp"]bool isPermutation(int tal, vector <int> vektor ){
vector <int> temp = tillVektor(tal);
if (temp.size() != vektor.size())
return false;
sort(temp.begin(), temp.end());
sort(vektor.begin(), vektor.end());
if (vektor == temp)
return true;
return false;

}[/syntax]

I guess that is a better algorithm

[The Insomniacs Dream]

<------- = a noob

...could i get an explination of all this?

[Blueteeth]

That's far better , it's O(nlgn) .
As for the O(-) thing , it's called Big-Oh Notation , it's a way for describing the complexity of an algorithm .