Language: C++

#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000
#define int long long

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N; cin >> N;
    vector<int> L(N);
    rep(i, N) cin >> L[i];
    sort(L.begin(), L.end());
    L.push_back(INF);
    int ans = 0;
    rep(i, N - 2) {
        REP(j, i + 1, N - 2) {
            int upper = L[i] + L[j];
            int lower = L[j] - L[i];
            auto itr1 = upper_bound(L.begin()+j+1, L.end(), lower);
            auto itr2 = lower_bound(L.begin()+j+1, L.end(), upper);
            itr2--;
            //cout << ab <<  " " << (L.end() - itr) << " " << *itr << endl;
            //cout << max(0,itr2 - itr1 + 1) << endl;
            //if (*itr2 == INF) continue;
            ans += max(0,itr2 - itr1 + 1);
            //cout << *itr2 << " " << *itr1 << endl;
            //dump(L.end() - itr);
        }
    }
    cout << ans << endl;
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:34:23: error: no matching function for call to 'max(int, __gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type)'
   34 |             ans += max(0,itr2 - itr1 + 1);
      |                    ~~~^~~~~~~~~~~~~~~~~~~
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:34:23: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type' {aka 'long int'})
   34 |             ans += max(0,itr2 - itr1 + 1);
      |                    ~~~^~~~~~~~~~~~~~~~~~~
/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:34:23: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   34 |             ans += max(0,itr2 - itr1 + 1);
      |                    ~~~^~~~~~~~~~~~~~~~~~~