Language: C++

#include <stack>
#include <queue>
#include <cstdio>
#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <math.h>
#include <string>
 
using namespace std;

#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,n0,n) for(int i=n0;i<n;i++)
#define Com(i,j,n) for(int i=0;i<n-1;i++)for(int j=i+1;j<n;j++)
#define INF (1<<29)
#define test cout << "test" << endl;
#define NNN_MAX 100010
typedef pair<int,int> P;

int main (){

	int NNN;
	cin >>NNN;
	int temp;
	vector <int> a;
	bool po[NNN];
	rep(i,NNN){
		cin >> temp;
		a.push_back(temp);
		po[i]=true;
	}
	if(NNN==2){
		cout << a[0] << " " << a[1] << endl;
		return 0;
	}
	//NNN>2

	sort(a.begin(),a.end(),greater<int>());
	int max=a[0];

	unique(a.begin(),a.end());
	if(a.size()==1){
		cout << a[0] <<" " << a[0] << endl;
	}

	//maxの半分に一番近い数字を探そう
	int temp1,temp2;
	int pointer=0;
	int halfmax = (max+max%2)/2;


	//最初に真ん中にポインターを置く
	pointer=(a.size()-a.size()%2)/2; 

	int count =1;
	//終了条件 = abs(a[pointer-1],max/2)
	while(1){
		
		//po[pointer]=false;
		//丁度半分、0にきちゃった、上から2番めのところまで来ちゃった
		if(a[pointer]==halfmax){
			break;
		}
		if(pointer <= 0){
			if(abs(halfmax,a[0])>=abs(halfmax,a[1])){
				pointer =1;
				break;
			}
			else {
				pointer =0;
				break;
			}
		}
		if(pointer == a.size()-1){
			if(abs(halfmax,a[pointer])>=abs(halfmax,a[pointer-1])){
				pointer --;
				break;
			}
			else {
				break;
			}
		}

		//前後が今よりも悪くなる＝今が最適
		if(abs(a[pointer],halfmax)<=abs(a[pointer-1],halfmax) && abs(a[pointer],halfmax)<=abs(a[pointer+1],halfmax)){
			break;
		}

		if(a[pointer] < halfmax){
			count ++;
			pointer = pointer - floor(a.size()/pow(2,count))-1;
			if(po[pointer] == false){
				break;
			}

		}
		if(a[pointer] > halfmax){
			count ++;
			pointer = pointer + floor(a.size()/pow(2,count))+1;
			if(po[pointer] == false ){
				break;
			}

		}



	}

	cout << a[0] << " " << a[pointer] << endl;

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:41:15: warning: ignoring return value of '_FIter std::unique(_FIter, _FIter) [with _FIter = __gnu_cxx::__normal_iterator<int*, vector<int> >]', declared with attribute 'nodiscard' [-Wunused-result]
   41 |         unique(a.begin(),a.end());
      |         ~~~~~~^~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:6:
/usr/include/c++/14/bits/stl_algo.h:891:5: note: declared here
  891 |     unique(_ForwardIterator __first, _ForwardIterator __last)
      |     ^~~~~~
a.cc:65:31: error: no matching function for call to 'abs(int&, __gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type&)'
   65 |                         if(abs(halfmax,a[0])>=abs(halfmax,a[1])){
      |                            ~~~^~~~~~~~~~~~~~
In file included from /usr/include/c++/14/cstdlib:79,
                 from /usr/include/c++/14/ext/string_conversions.h:43,
                 from /usr/include/c++/14/bits/basic_string.h:4154,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:4:
/usr/include/stdlib.h:980:12: note: candidate: 'int abs(int)'
  980 | extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;
      |            ^~~
/usr/include/stdlib.h:980:12: note:   candidate expects 1 argument, 2 provided
In file included from /usr/include/c++/14/cstdlib:81:
/usr/include/c++/14/bits/std_abs.h:137:3: note: candidate: 'constexpr __float128 std::abs(__float128)'
  137 |   abs(__float128 __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:137:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:85:3: note: candidate: 'constexpr __int128 std::abs(__int128)'
   85 |   abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:85:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:79:3: note: candidate: 'constexpr long double std::abs(long double)'
   79 |   abs(long double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:79:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:75:3: note: candidate: 'constexpr float std::abs(float)'
   75 |   abs(float __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:75:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:71:3: note: candidate: 'constexpr double std::abs(double)'
   71 |   abs(double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:71:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:61:3: note: candidate: 'long long int std::abs(long long int)'
   61 |   abs(long long __x) { return __builtin_llabs (__x); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:61:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:56:3: note: candidate: 'long int std::abs(long int)'
   56 |   abs(long __i) { return __builtin_labs(__i); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:56:3: note:   candidate expects 1 argument, 2 provided
a.cc:65:50: error: no matching function for call to 'abs(int&, __gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type&)'
   65 |                         if(abs(halfmax,a[0])>=abs(halfmax,a[1])){
      |                                               ~~~^~~~~~~~~~~~~~
/usr/include/stdlib.h:980:12: note: candidate: 'int abs(int)'
  980 | extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;
      |            ^~~
/usr/include/stdlib.h:980:12: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:137:3: note: candidate: 'constexpr __float128 std::abs(__float128)'
  137 |   abs(__float128 __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:137:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:85:3: note: candidate: 'constexpr __int128 std::abs(__int128)'
   85 |   abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:85:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:79:3: note: candidate: 'constexpr long double std::abs(long double)'
   79 |   abs(long double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:79:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:75:3: note: candidate: 'constexpr float std::abs(float)'
   75 |   abs(float __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:75:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:71:3: note: candidate: 'constexpr double std::abs(double)'
   71 |   abs(double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:71:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:61:3: note: candidate: 'long long int std::abs(long long int)'
   61 |   abs(long long __x) { return __builtin_llabs (__x); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:61:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:56:3: note: candidate: 'long int std::abs(long int)'
   56 |   abs(long __i) { return __builtin_labs(__i); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:56:3: note:   candidate expects 1 argument, 2 provided
a.cc:75:31: error: no matching function for call to 'abs(int&, __gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type&)'
   75 |                         if(abs(halfmax,a[pointer])>=abs(halfmax,a[pointer-1])){
      |                            ~~~^~~~~~~~~~~~~~~~~~~~
/usr/include/stdlib.h:980:12: note: candidate: 'int abs(int)'
  980 | extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;
      |            ^~~
/usr/include/stdlib.h:980:12: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:137:3: note: candidate: 'constexpr __float128 std::abs(__float128)'
  137 |   abs(__float128 __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:137:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:85:3: note: candidate: 'constexpr __int128 std::abs(__int128)'
   85 |   abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:85:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:79:3: note: candidate: 'constexpr long double std::abs(long double)'
   79 |   abs(long double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:79:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:75:3: note: candidate: 'constexpr float std::abs(float)'
   75 |   abs(float __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:75:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:71:3: note: candidate: 'constexpr double std::abs(double)'
   71 |   abs(double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:71:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:61:3: note: candidate: 'long long int std::abs(long long int)'
   61 |   abs(long long __x) { return __builtin_llabs (__x); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:61:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:56:3: note: candidate: 'long int std::abs(long int)'
   56 |   abs(long __i) { return __builtin_labs(__i); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:56:3: note:   candidate expects 1 argument, 2 provided
a.cc:75:56: error: no matching function for call to 'abs(int&, __gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type&)'
   75 |                         if(abs(halfmax,a[pointer])>=abs(halfmax,a[pointer-1])){
      |                                                     ~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/stdlib.h:980:12: note: candidate: 'int abs(int)'
  980 | extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;
      |            ^~~
/usr/include/stdlib.h:980:12: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:137:3: note: candidate: 'constexpr __float128 std::abs(__float128)'
  137 |   abs(__float128 __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:137:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:85:3: note: candidate: 'constexpr __int128 std::abs(__int128)'
   85 |   abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:85:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:79:3: note: candidate: 'constexpr long double std::abs(long double)'
   79 |   abs(long double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:79:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:75:3: note: candidate: 'constexpr float std::abs(float)'
   75 |   abs(float __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:75:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:71:3: note: candidate: 'constexpr double std::abs(double)'
   71 |   abs(double __x)
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:71:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:61:3: note: candidate: 'long long int std::abs(long long int)'
   61 |   abs(long long __x) { return __builtin_llabs (__x); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:61:3: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/std_abs.h:56:3: note: candidate: 'long int std::abs(long int)'
   56 |   abs(long __i) { return __builtin_labs(__i); }
      |   ^~~
/usr/include/c++/14/bits/std_abs.h:56:3: note:   candidate expects 1 argument, 2 provided
a.cc:85:23: error: no matching function for call to 'abs(__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type&, int&)'
   85 |