Language: C++

#include<bits/stdc++.h>
typedef long long int ll;
typedef unsigned long long int ull;
#define BIG_NUM 2000000000
#define HUGE_NUM 99999999999999999
#define MOD 1000000007
#define EPS 0.000000001
using namespace std;


#define NUM 100005

int N;
map<int,int> MAP;

int main(){

	int table[NUM],count[NUM];

	scanf("%d",&N);

	for(int i = 0; i < N; i++){

		count[i] = 0;
	}

	int tmp;
	vector<int> V;

	for(int i = 0; i < N; i++){

		scanf("%d",&tmp);
		table[i] = tmp;
		V.push_back(tmp);
	}

	sort(V.begin(),V.end());
	V.erase(unique(V.begin(),V.end()),V.end());

	for(int i = 0; i < V.size(); i++){

		MAP[V[i]] = i;
	}

	for(int i = 0; i < N; i++){

		count[MAP[table[i]]]++; //辺の本数を数える
	}

	ll max_1 = 0,max_2 = 0,max_seihou = 0;

	for(int i = 0; i < V.size(); i++){

		if(count[i] >= 4){

			max_seihou = V[i];
		}

		if(count[i] >= 2){
			max_2 = max_1;
			max_1 = V[i];
		}
	}

	printf("%lld\n",max(0,max(max_seihou*max_seihou,max_1*max_2)));

	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:65:28: error: no matching function for call to 'max(int, const long long int&)'
   65 |         printf("%lld\n",max(0,max(max_seihou*max_seihou,max_1*max_2)));
      |                         ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included 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_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:65:28: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long long int')
   65 |         printf("%lld\n",max(0,max(max_seihou*max_seihou,max_1*max_2)));
      |                         ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:65:28: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   65 |         printf("%lld\n",max(0,max(max_seihou*max_seihou,max_1*max_2)));
      |                         ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~