removing duplicate vector from 2d vector

Question

I have coded this to remove similar vector from 2d vector, this can be for any numbers of vector inside 2d vector but for example I have taken only 3 vector.

here, {1,2,3,4} is similar to {3,2,1,4} so I have to remove {3,2,1,4}.

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
    vector<vector<int> > v = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 3, 2, 1, 4 } };
    vector<int> r, c;

    // sorting elements
    for (auto row = v.begin(); row != v.end(); row++) {
        sort(row->begin(), row->end());
    }

    // Deleting Duplicates
    for (auto row = v.begin(); row != v.end() - 1; row++) {
        r.clear();
        c.clear();
        cout << endl
             << endl;
        for (auto col = row->begin(); col != row->end(); col++) {
            r.push_back(*col);
        }

        for (auto cr = row + 1; cr != v.end(); cr++) {
            for (auto cc = cr->begin(); cc != cr->end(); cc++) {
                c.push_back(*cc);
            }

            if (r == c)
                v.erase(cr->begin(), cr->end());
            c.clear();
        }
        cout << endl;
    }

    // Printing
    for (auto row = v.begin(); row != v.end(); row++) {
        for (auto col = row->begin(); col != row->end(); col++) {
            cout << *col << " ";
        }
    }
}

error: no matching function for call to ‘std::vector >::erase(std::vector::iterator, std::vector::iterator)'

Answer 1

You can easily sort your 2d vector's elements and then compare them one by one. Here, one function compares two 1d vectors and returns the result.

Note: When an element of your 2d vector gets deleted, the next element replaces it, so you shouldn't increase the target index (index k in my code). Increase the index only if these two elements are not equal.

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

bool twoVectorsAreEqual(vector<int> first_vec, vector<int> second_vec) {

    sort(first_vec.begin(), first_vec.end());
    sort(second_vec.begin(), second_vec.end());
    return (first_vec == second_vec);
}

int main(){

    vector<vector<int>> double_vec /* = some velue*/;

    for (int i = 0; i < double_vec.size() - 1; i++) {
        for (int k = i + 1; k < double_vec.size();) {

            if (twoVectorsAreEqual(double_vec[i], double_vec[k])) {
                double_vec.erase(double_vec.begin() + k);                
            else
                k++;                
        }
    }
}