Language: C++

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

int a[maxn];

int main() 
{
    int n,a;
    
    cin >> n;
    
	long long ans = 0;
    
	for(int i=0;i<n;i++) 
	{
        int x,y;
        
        cin >> x >> y;
        
		a[i]=x+y;
        
		ans-=y;
    }
    
	sort(a,a+n);
    
	int cur=1;
    
	for(int i=n-1;i>=0;i--) 
	{
        if(cur) 
			ans+=a[i];
        
		cur^=1;
    }
    
	cout << ans << endl;
    
	return 0;
}

Compiler output:
a.cc:4:7: error: 'maxn' was not declared in this scope
    4 | int a[maxn];
      |       ^~~~
a.cc: In function 'int main()':
a.cc:20:18: error: invalid types 'int[int]' for array subscript
   20 |                 a[i]=x+y;
      |                  ^
a.cc:32:31: error: invalid types 'int[int]' for array subscript
   32 |                         ans+=a[i];
      |                               ^
In file included from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algo.h: In instantiation of 'void std::__insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]':
/usr/include/c++/14/bits/stl_algo.h:1817:25:   required from 'void std::__final_insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1817 |           std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1908:31:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1908 |           std::__final_insertion_sort(__first, __last, __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = int]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:25:6:   required from here
   25 |         sort(a,a+n);
      |         ~~~~^~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1780:17: error: no type named 'value_type' in 'struct std::iterator_traits<int>'
 1780 |                 __val = _GLIBCXX_MOVE(*__i);
      |                 ^~~~~
In file included from /usr/include/c++/14/bits/stl_pair.h:61,
                 from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60:
/usr/include/c++/14/bits/stl_algo.h:1780:25: error: invalid type argument of unary '*' (have 'int')
 1780 |                 __val = _GLIBCXX_MOVE(*__i);
      |                         ^~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1782:15: error: invalid type argument of unary '*' (have 'int')
 1782 |               *__first = _GLIBCXX_MOVE(__val);
      |               ^~~~~~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:71:
/usr/include/c++/14/bits/predefined_ops.h: In instantiation of 'constexpr bool __gnu_cxx::__ops::_Iter_less_iter::operator()(_Iterator1, _Iterator2) const [with _Iterator1 = int; _Iterator2 = int]':
/usr/include/c++/14/bits/stl_algo.h:1777:14:   required from 'void std::__insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1777 |           if (__comp(__i, __first))
      |               ~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1817:25:   required from 'void std::__final_insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1817 |           std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1908:31:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1908 |           std::__final_insertion_sort(__first, __last, __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = int]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:25:6:   required from here
   25 |         sort(a,a+n);
      |         ~~~~^~~~~~~
/usr/include/c++/14/bits/predefined_ops.h:45:16: error: invalid type argument of unary '*' (have 'int')
   45 |       { return *__it1 < *__it2; }
      |                ^~~~~~
/usr/include/c++/14/bits/predefined_ops.h:45:25: error: invalid type argument of unary '*' (have 'int')
   45 |       { return *__it1 < *__it2; }
      |                         ^~~~~~
In file included from /usr/include/c++/14/bits/stl_algo.h:61:
/usr/include/c++/14/bits/stl_heap.h: In instantiation of 'void std::__make_heap(_RandomAccessIterator, _RandomAccessIterator, _Compare&) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]':
/usr/include/c++/14/bits/stl_algo.h:1593:23:   required from 'void std::__heap_select(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1593 |       std::__make_heap(__first, __middle, __comp);
      |       ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1868:25:   required from 'void std::__partial_sort(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1868 |       std::__heap_select(__first, __middle, __last, __comp);
      |       ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1884:27:   required from 'void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = int; _Size = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1884 |               std::__partial_sort(__first, __last, __last, __comp);
      |               ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1905:25:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1905 |           std::__introsort_loop(__first, __last,
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
 1906 |                                 std::__lg(__last - __first) * 2,
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1907 |                                 __comp);
      |                                 ~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = int]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:25:6:   required from here
   25 |         sort(a,a+n);
      |         ~~~~^~~~~~~
/usr/include/c++/14/bits/stl_heap.h:344:11: error: no type named 'value_type' in 'struct std::iterator_traits<int>'
  344 |           _ValueType;
      |           ^~~~~~~~~~
/usr/include/c++/14/bits/stl_heap.h:346:11: error: no type named 'difference_type' in 'struct std::iterator_traits<int>'
  346 |           _DistanceType;
      |           ^~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_heap.h: In instantiation of 'void std::__pop_heap(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare&) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]':
/usr/include/c++/14/bits/stl_algo.h:1596:19:   required from 'void std::__heap_select(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1596 |           std::__pop_heap(__first, __middle, __i, __comp);
      |           ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1868:25:   required from 'void std::__partial_sort(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1868 |       std::__heap_select(__first, __middle, __last, __comp);
      |       ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1884:27:   required from 'void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = int; _Size = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1884 |               std::__partial_sort(__first, __last, __last, __comp);
      |               ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1905:25:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1905 |           std::__introsort_loop(__first, __last,
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
 1906 |                                 std::__lg(__last - __first) * 2,
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1907 |                                 __comp);
      |                                 ~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = int]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:25:6:   required from here
   25 |         sort(a,a+n);
      |         ~~~~^~~~~~~
/usr/include/c++/14/bits/stl_heap.h:258:9: error: no type named 'value_type' in 'struct std::iterator_traits<int>'
  258 |         _ValueType;
      |         ^~~~~~~~~~
/usr/include/c++/14/bits/stl_heap.h:260:9: error: no type named 'difference_type' in 'struct std::iterator_traits<int>'
  260 |         _DistanceType;
      |         ^~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_heap.h:262:28: