How to remove duplicates in particular set of data? - c++

Question

Let's suppose we have two childs who want to get same number or coins (coin nominals 1,2,6,12). Childs don't care about the value.
Example container of permutations which I want to share between two childs:
{1, 1, 1, 1, 1, 1},
{1, 1, 2, 2},
{1, 2, 1, 2},
{1, 2, 2, 1},
{2, 1, 1, 2},
{2, 1, 2, 1},
{2, 2, 1, 1}
Now I`d like to have collections without duplicates:
child A child B
2 2 1 1
2 1 2 1
1 1 2 2
1 1 1 1 1 1
That permutations are wrong:
1 2 1 2
1 2 2 1
2 1 1 2
because
child A child B
1 2 1 2
is permutation of
child A child B
2 1 2 1
which we already have. These collections: 1 2 2 1 and 2 1 1 2 are permutations, as well.
My solution is here, works correctly for that particular input but if you add more coins with different nominals, it doesn't!
#include <iostream>
#include <vector>
#include <unordered_set>
using namespace std;
int main()
{
vector<vector<int>> permutations =
{
{1, 1, 1, 1, 1, 1},
{1, 1, 2, 2},
{1, 2, 1, 2},
{1, 2, 2, 1},
{2, 1, 1, 2},
{2, 1, 2, 1},
{2, 2, 1, 1}
};
vector<pair<unordered_multiset<int>, unordered_multiset<int>>> childSubsets;
for(const auto &currentPermutation : permutations)
{
size_t currentPermutationSize = currentPermutation.size();
size_t currentPermutationHalfSize = currentPermutationSize / 2;
//left
unordered_multiset<int> leftSet;
for(int i=0;i<currentPermutationHalfSize;++i)
leftSet.insert(currentPermutation[i]);
bool leftSubsetExist = false;
for(const auto &subset : childSubsets)
{
if(subset.first == leftSet)
{
leftSubsetExist = true;
break;
}
}
//right
unordered_multiset<int> rightSet;
for(int i = currentPermutationHalfSize; i < currentPermutationSize; ++i)
rightSet.insert(currentPermutation[i]);
bool rightSubsetExist = false;
for(const auto &subset : childSubsets)
{
if(subset.second == rightSet)
{
rightSubsetExist = true;
break;
}
}
//summarize
if(!leftSubsetExist || !rightSubsetExist) childSubsets.push_back({leftSet, rightSet});
}
cout << childSubsets.size() << endl;
}
How to change the solution to make optimal and less complex?

Answer 1

You should add
if (leftSubsetExist)
continue;
after first cycle (as optimization)
Could you add some "wrong" permutations (with another coins)?