Language: C++

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace __gnu_pbds;
using namespace std;
#define ll long long
#define hii cout << "hii" << endl
#define int ll
#define endl '\n'
#define all(s) s.begin(), s.end()
 
template <class T> ostream& operator << (ostream &os, const vector<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T> ostream& operator << (ostream &os, const set<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T, class S> ostream& operator << (ostream &os, const pair<T, S> &v) { os << v.first << ' ' << v.second; return os; }
template <class T, class S> ostream& operator << (ostream &os, const unordered_map<T, S> &v) { for (auto i : v) os << '(' << i.first << "=>" << i.second << ')' << ' '; return os; } 
 
 
#ifndef ONLINE_JUDGE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
    template <class Arg1> void __f(const char* name, Arg1&& arg1) { cerr << name << " : " << arg1 << endl; }
    template <class Arg1, class... Args>
    void __f(const char* names, Arg1&& arg1, Args&&... args) {
        const char* sep = strchr(names + 1, ',');
        cerr.write(names, sep - names) << " : " << arg1 << "  ";
        __f(sep + 1, args...);
    }
#else
#define trace(...) 0
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define _CRT_SECURE_NO_WARNINGS
#endif // ifndef ONLINE_JUDGE
 
 
const int N = 5e5 + 5;
const int MAXN = 1e5 + 5;
const int mod = 1e9 + 7;
const int MOD = 1e9 + 7;
const int INF = 1e15;
const int LG = 21;
const long double PI = acos(-1);

int arr[N];

void solve() 
{
	precompute();
	int n, k;
	cin >> n >> k;
	int ret = 0;
	for(int i = 0; i <= n; i++)
	{
		arr[i] = i;
		if(i)
		{
			arr[i] = arr[i] + arr[i - 1];
		}
	}
	for(int i = k; i <= n + 1; i++)
	{
		int l1 = get(n - i + 1, n);
		int l2 = get(0, i - 1);
		ret += l1 - l2 + 1;
		ret %= mod;
	}
	cout << ret % mod << endl;
}

 
 
int32_t main() 
{	
    ios_base:: sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	    int t = 1;
	    // cin >> t;
	while(t--)solve();
	return 0;
}

Compiler output:
a.cc: In function 'void solve()':
a.cc:49:9: error: 'precompute' was not declared in this scope
   49 |         precompute();
      |         ^~~~~~~~~~
a.cc:63:29: error: no matching function for call to 'get(long long int, long long int&)'
   63 |                 int l1 = get(n - i + 1, n);
      |                          ~~~^~~~~~~~~~~~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 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_pair.h:1250:5: note: candidate: 'template<long unsigned int _Int, class _Tp1, class _Tp2> constexpr typename std::tuple_element<_Int, std::pair<_Tp1, _Tp2> >::type& std::get(pair<_Tp1, _Tp2>&)'
 1250 |     get(pair<_Tp1, _Tp2>& __in) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1250:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1255:5: note: candidate: 'template<long unsigned int _Int, class _Tp1, class _Tp2> constexpr typename std::tuple_element<_Int, std::pair<_Tp1, _Tp2> >::type&& std::get(pair<_Tp1, _Tp2>&&)'
 1255 |     get(pair<_Tp1, _Tp2>&& __in) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1255:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1260:5: note: candidate: 'template<long unsigned int _Int, class _Tp1, class _Tp2> constexpr const typename std::tuple_element<_Int, std::pair<_Tp1, _Tp2> >::type& std::get(const pair<_Tp1, _Tp2>&)'
 1260 |     get(const pair<_Tp1, _Tp2>& __in) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1260:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1265:5: note: candidate: 'template<long unsigned int _Int, class _Tp1, class _Tp2> constexpr const typename std::tuple_element<_Int, std::pair<_Tp1, _Tp2> >::type&& std::get(const pair<_Tp1, _Tp2>&&)'
 1265 |     get(const pair<_Tp1, _Tp2>&& __in) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1265:5: note:   candidate expects 1 argument, 2 provided
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/tuple:2445:5: note: candidate: 'template<long unsigned int __i, class ... _Elements> constexpr std::__tuple_element_t<__i, std::tuple<_Elements ...> >& std::get(tuple<_Elements ...>&)'
 2445 |     get(tuple<_Elements...>& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2445:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2451:5: note: candidate: 'template<long unsigned int __i, class ... _Elements> constexpr std::__tuple_element_t<__i, std::tuple<_Elements ...> >& std::get(const tuple<_Elements ...>&)'
 2451 |     get(const tuple<_Elements...>& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2451:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2457:5: note: candidate: 'template<long unsigned int __i, class ... _Elements> constexpr std::__tuple_element_t<__i, std::tuple<_Elements ...> >&& std::get(tuple<_Elements ...>&&)'
 2457 |     get(tuple<_Elements...>&& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2457:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2466:5: note: candidate: 'template<long unsigned int __i, class ... _Elements> constexpr std::__tuple_element_t<__i, std::tuple<_Elements ...> >&& std::get(const tuple<_Elements ...>&&)'
 2466 |     get(const tuple<_Elements...>&& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2466:5: note:   candidate expects 1 argument, 2 provided
In file included from /usr/include/c++/14/functional:65,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53:
/usr/include/c++/14/array:390:5: note: candidate: 'template<long unsigned int _Int, class _Tp, long unsigned int _Nm> constexpr _Tp& std::get(array<_Tp, _Nm>&)'
  390 |     get(array<_Tp, _Nm>& __arr) noexcept
      |     ^~~
/usr/include/c++/14/array:390:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/array:399:5: note: candidate: 'template<long unsigned int _Int, class _Tp, long unsigned int _Nm> constexpr _Tp&& std::get(array<_Tp, _Nm>&&)'
  399 |     get(array<_Tp, _Nm>&& __arr) noexcept
      |     ^~~
/usr/include/c++/14/array:399:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/array:408:5: note: candidate: 'template<long unsigned int _Int, class _Tp, long unsigned int _Nm> constexpr const _Tp& std::get(const array<_Tp, _Nm>&)'
  408 |     get(const array<_Tp, _Nm>& __arr) noexcept
      |     ^~~
/usr/include/c++/14/array:408:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/array:417:5: note: candidate: 'template<long unsigned int _Int, class _Tp, long unsigned int _Nm> constexpr const _Tp&& std::get(const array<_Tp, _Nm>&&)'
  417 |     get(const array<_Tp, _Nm>&& __arr) noexcept
      |     ^~~
/usr/include/c++/14/array:417:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1272:5: note: candidate: 'template<class _Tp, class _Up> constexpr _Tp& std::get(pair<_T1, _T2>&)'
 1272 |     get(pair<_Tp, _Up>& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1272:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1277:5: note: candidate: 'template<class _Tp, class _Up> constexpr const _Tp& std::get(const pair<_T1, _T2>&)'
 1277 |     get(const pair<_Tp, _Up>& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1277:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1282:5: note: candidate: 'template<class _Tp, class _Up> constexpr _Tp&& std::get(pair<_T1, _T2>&&)'
 1282 |     get(pair<_Tp, _Up>&& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1282:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1287:5: note: candidate: 'template<class _Tp, class _Up> constexpr const _Tp&& std::get(const pair<_T1, _T2>&&)'
 1287 |     get(const pair<_Tp, _Up>&& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1287:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1292:5: note: candidate: 'template<class _Tp, class _Up> constexpr _Tp& std::get(pair<_Up, _Tp>&)'
 1292 |     get(pair<_Up, _Tp>& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1292:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1297:5: note: candidate: 'template<class _Tp, class _Up> constexpr const _Tp& std::get(const pair<_Up, _Tp>&)'
 1297 |     get(const pair<_Up, _Tp>& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1297:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1302:5: note: candidate: 'template<class _Tp, class _Up> constexpr _Tp&& std::get(pair<_Up, _Tp>&&)'
 1302 |     get(pair<_Up, _Tp>&& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1302:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_pair.h:1307:5: note: candidate: 'template<class _Tp, class _Up> constexpr const _Tp&& std::get(const pair<_Up, _Tp>&&)'
 1307 |     get(const pair<_Up, _Tp>&& __p) noexcept
      |     ^~~
/usr/include/c++/14/bits/stl_pair.h:1307:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2476:5: note: candidate: 'template<long unsigned int __i, class ... _Elements> constexpr std::__enable_if_t<(__i >= sizeof... (_Types))> std::get(const tuple<_Elements ...>&)' (deleted)
 2476 |     get(const tuple<_Elements...>&) = delete;
      |     ^~~
/usr/include/c++/14/tuple:2476:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2483:5: note: candidate: 'template<class _Tp, class ... _Types> constexpr _Tp& std::get(tuple<_Elements ...>&)'
 2483 |     get(tuple<_Types...>& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2483:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2494:5: note: candidate: 'template<class _Tp, class ... _Types> constexpr _Tp&& std::get(tuple<_Elements ...>&&)'
 2494 |     get(tuple<_Types...>&& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2494:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2505:5: note: candidate: 'template<class _Tp, class ... _Types> constexpr const _Tp& std::get(const tuple<_Elements ...>&)'
 2505 |     get(const tuple<_Types...>& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2505:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/tuple:2517:5: note: candidate: 'template<class _Tp, class ... _Types> constexpr const _Tp&& std::get(const tuple<_Elements ...>&&)'
 2517 |     get(const tuple<_Types...>&& __t) noexcept
      |     ^~~
/usr/include/c++/14/tuple:2517:5: note:   candidate expects 1 argument, 2 provided
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:80:
/usr/include/c++/14/variant:1715:5: note: candidate: 'template<long unsigned int _Np, class ... _Types> constexpr std::variant_alternative_t<_Np, std::variant<_Types ...> >& std::get(variant<_Types ...>&)'
 1715 |     get(variant<_Types...>& __v)
      |     ^~~
/usr/include/c++/14/variant:1715:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/variant:1726:5: note: candidate: 'template<long unsigned int _Np, class ... _Types> constexpr std::variant_alternative_t<_Np, std::variant<_Types ...> >&& std::get(variant<_Types ...>&&)'
 1726 |     get(variant<_Types...>&& __v)
      |     ^~~
/usr/include/c++/14/variant:1726:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/variant:1737:5: note: candidate: 'template<long unsigned int _Np, class ... _Types> constexpr std::variant_alternative_t<_Np, std::variant<_Types ...> >& std::get(const variant<_Types ...>&)'
 1737 |     get(const variant<_Types...>& __v)