Language: C++

#include<bits/stdc++.h>
using namespace std;

#define int long long

typedef  pair<int, int> iPair;
struct Graph
{
    int V, E;
    vector< pair<int, iPair> > edges;
    
    Graph(int V, int E)
    {
        this->V = V;
        this->E = E;
    }
    void addEdge(int u, int v, int w)
    {
        edges.push_back({w, {u, v}});
    }
    int kruskalMST();
};

vector< iPair > edges2;
bool cmp1(int a, int b){
	if(edges2[a].first > edges2[b].first || (edges2[a].second > edges2[b].second && edges2[a].first == edges2[b].first)) return true;
	else return false;
}

bool cmp2(int a, int b){
	if(edges2[a].second > edges2[b].second || (edges2[a].first > edges2[b].first && edges2[a].second == edges2[b].second)) return true;
	else return false;
}

struct DisjointSets
{
    int *parent, *rnk;
    int n;
    DisjointSets(int n)
    {
        this->n = n;
        parent = new int[n+1];
        rnk = new int[n+1];
        for (int i = 0; i <= n; i++)
        {
            rnk[i] = 0;
            parent[i] = i;
        }
    }
    int find(int u)
    {
        if (u != parent[u])
            parent[u] = find(parent[u]);
        return parent[u];
    }

    void merge(int x, int y)
    {
        x = find(x), y = find(y);
        if (rnk[x] > rnk[y])
            parent[y] = x;
        else
            parent[x] = y;

        if (rnk[x] == rnk[y])
            rnk[y]++;
    }
};

int Graph::kruskalMST()
{
    int mst_wt = 0;
    sort(edges.begin(), edges.end());
    DisjointSets ds(V);
    vector< pair<int, iPair> >::iterator it;
    for (it=edges.begin(); it!=edges.end(); it++)
    {
        int u = it->second.first;
        int v = it->second.second;

        int set_u = ds.find(u);
        int set_v = ds.find(v);
        if (set_u != set_v)
        {
            cout << u << " - " << v << endl;
            mst_wt += it->first;
            ds.merge(set_u, set_v);
        }
    }

    return mst_wt;
}

int main()
{
	int n, x, y;
	cin >> n;
	for(int i = 0; i < n; i++){
		cin >> x >> y;
		edges2.push_back(make_pair(x, y));
	} 
    Graph(n, 2*(n-1));
    sort(edges2, edges2 + n, cmp1);
    for(int i = 0; i < n-1; i++) Graph.push_back(i, i + 1, min(abs(edges2[i].first-edges2[i+1].first), abs(edges2[i].second-edges2[i+1].second));
    sort(edges2, edges2 + n, cmp2);
    for(int i = 0; i < n-1; i++) Graph.push_back(i, i + 1, min(abs(edges2[i].first-edges2[i+1].first), abs(edges2[i].second-edges2[i+1].second));
    int mst_wt = g.kruskalMST();
    cout << mst_wt;
    return 0;
}

Compiler output:
cc1plus: error: '::main' must return 'int'
a.cc: In function 'int main()':
a.cc:103:25: error: no match for 'operator+' (operand types are 'std::vector<std::pair<long long int, long long int> >' and 'long long int')
  103 |     sort(edges2, edges2 + n, cmp1);
      |                  ~~~~~~ ^ ~
      |                  |        |
      |                  |        long long int
      |                  std::vector<std::pair<long long int, long long int> >
In file included from /usr/include/c++/14/bits/stl_algobase.h:67,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:627:5: note: candidate: 'template<class _Iterator> constexpr std::reverse_iterator<_Iterator> std::operator+(typename reverse_iterator<_Iterator>::difference_type, const reverse_iterator<_Iterator>&)'
  627 |     operator+(typename reverse_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:627:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'long long int'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note: candidate: 'template<class _Iterator> constexpr std::move_iterator<_IteratorL> std::operator+(typename move_iterator<_IteratorL>::difference_type, const move_iterator<_IteratorL>&)'
 1798 |     operator+(typename move_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'long long int'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/basic_string.h:3598:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3598 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3598:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3616:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3616 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3616:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   mismatched types 'const _CharT*' and 'std::vector<std::pair<long long int, long long int> >'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3635:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3635 |     operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3635:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'long long int'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3652:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3652 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3652:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3670:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)'
 3670 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3670:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3682:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3682 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3682:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3689:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3689 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3689:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3696:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3696 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3696:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3719:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3719 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3719:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   mismatched types 'const _CharT*' and 'std::vector<std::pair<long long int, long long int> >'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3726:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3726 |     operator+(_CharT __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3726:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'long long int'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3733:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const _CharT*)'
 3733 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3733:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
  103 |     sort(edges2, edges2 + n, cmp1);
      |                           ^
/usr/include/c++/14/bits/basic_string.h:3740:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, _CharT)'
 3740 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3740:5: note:   template argument deduction/substitution failed:
a.cc:103:27: note:   'std::vector<std::pair<long long int, long long int> >' is not derive