Language: C++

#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

int n;
vi a;

int main(){
	cin>>n;
	a=vi(n);
	for(int i=0;i<n;i++) cin>>a[i];
	sort(a.begin(),a.end());
	int res=0;
	for(int i=0;i<n;i++) for(int j=i+1;j<n;j++) res+=max(0,i-(upper_bound(a.begin(),a.end(),a[j]-a[i])-a.begin()));
	cout<<res<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:37:61: error: no matching function for call to 'max(int, __gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type)'
   37 |         for(int i=0;i<n;i++) for(int j=i+1;j<n;j++) res+=max(0,i-(upper_bound(a.begin(),a.end(),a[j]-a[i])-a.begin()));
      |                                                          ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:37:61: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'})
   37 |         for(int i=0;i<n;i++) for(int j=i+1;j<n;j++) res+=max(0,i-(upper_bound(a.begin(),a.end(),a[j]-a[i])-a.begin()));
      |                                                          ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/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:37:61: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   37 |         for(int i=0;i<n;i++) for(int j=i+1;j<n;j++) res+=max(0,i-(upper_bound(a.begin(),a.end(),a[j]-a[i])-a.begin()));
      |                                                          ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~