How to do sorting and applying unique on vector of vectors?

Question

I need to keep only the unique arrays in a vector. I am not getting how to do it just using std algorithms. I tried different approaches, but nothing worked.

Code:

include <iostream>
#include <vector>
#include <array>
#include <algorithm>
using vec3 = std::array<int,3>;

struct vec3comp{
    bool operator()(const vec3 &lhs, const vec3 &rhs){
        return lhs[0]< rhs[0] && lhs[1] < rhs[1] && lhs[2] < rhs[2];
    }
} mycomp;

int main(){

    std::vector<std::array<int,3>>vec;
    
    vec.push_back({1,2,3});
    vec.push_back({1,3,2});
    vec.push_back({2,1,3});
    vec.push_back({1,3,3});
    vec.push_back({1,2,3});
    vec.push_back({1,2,4});
    vec.push_back({2,4,5});
    vec.push_back({3,5,6});
    vec.push_back({4,5,6});
    vec.push_back({5,4,6});
    vec.push_back({6,4,5});
    vec.push_back({5,4,3});
    vec.push_back({5,4,2});
    vec.push_back({5,4,6});
    vec.push_back({2,4,5});
    vec.push_back({3,5,6});
    vec.push_back({1,3,3});
    vec.push_back({2,1,3});
    //How should be the comp function 
   

     
        std::sort(vec.begin(),vec.end(),mycomp);
     for(auto i(0);i<vec.size();++i){
         std::cout<<vec.at(i)[0]<<" "<<vec.at(i)[1]<<" "<<vec.at(i)[2]<<std::endl;
     }
    //apply unique on vec after sort

    std::cout<<vec.size()<<std::endl;

    
    return 0;
}

After sorting and unique, vector of arrays should be:

{{1,2,3},{1,2,4},{1,3,2},{1,3,3},{2,1,3},{2,4,5},{3,4,5},{3,5,6},{4,5,6},{5,4,2},{5,4,3},{5,4,6},{6,4,5}}

Could someone help me with this problem?

Thanks in advance

Answer 1

using a std::set should solve your problem

std::set<vec3> s{vec.begin(),vec.end()};
vec.assign(s.begin(),s.end());

you can also add a custom compare class as a template parameter