Language: C++

#include <bits/stdc++.h>

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define endl "\n"
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rrep(i, n) for(int i = ((int)(n)-1); i >= 0; i--)
#define all(x) (x).begin(),(x).end()
 
using namespace std;
using ll = long long;
 
struct edge { int to, cost; };
 
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> P;
 
const int INF = ~(1<<31);
const int MOD = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);
 
const int mx4[] = {0,1,0,-1};
const int my4[] = {1,0,-1,0};
const int mx8[] = {0,1,1,1,0,-1,-1,-1};
const int my8[] = {1,1,0,-1,-1,-1,0,1};

int main()
{
	int n;
	cin >> n;
	vi l(n);
	rep(i,n) cin >> l[i];
	sort(all(l));
	ll ans = 0;
	int left,right;
	/**
	 * (a-b<c<a+b)&&(b-a<c<a+b)なので
	 * a<b<cとすると
	 * b<c<b+a
	 */ 
	for(int a = 0; a < l.size(); a++){
		for(int b = a+1; b < l.size(); b++){
			left = l[b];
			right = l[b]+l[a];
			ans += max(0,lower_bound(all(l),right)-lower_bound(all(l),left+1));
		}
	}
	cout << ans << endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:46:35: error: no matching function for call to 'max(int, __gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type)'
   46 |                         ans += max(0,lower_bound(all(l),right)-lower_bound(all(l),left+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:46:35: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'})
   46 |                         ans += max(0,lower_bound(all(l),right)-lower_bound(all(l),left+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:46:35: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   46 |                         ans += max(0,lower_bound(all(l),right)-lower_bound(all(l),left+1));
      |                                ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~