Language: C++

#include<bits/stdc++.h>
using namespace std;
long long n,a,b,i,j,Mod=1000000007,k,ans1,ans2;
long long x1=1,x2=1,y1=1,y2=1;
long long get(long long x,long long y){
    long long ans=1,cur=x;
    while(y){
        if(y & 1){
            ans = ans * cur % Mod;
        }
        cur = cur * cur % Mod;
        y >>= 1;
    }
    return ans;
}
int main(){
    
    cin>>n>>a>>b;
    k=get(2,n)-1;
    
    for(i=n-a+1;i<=n;i++)x1=x1*i%Mod;
    for(i=1;i<=a;i++)y1=y1*i%Mod;
    
    for(i=n-b+1;i<=n;i++)x2=x2*i%Mod;
    for(i=1;i<=b;i++)y2=y2*i%Mod;
    
    ans1=(x1*get(y1,Mod-2))%Mod;
    ans2=(x2*get(y2,Mod-2))%Mod;
    
    cout<<(k-ans1-ans2+3*Mod)%Mod<<endl;
}

Compiler output:
a.cc:4:21: error: 'long long int y1' redeclared as different kind of entity
    4 | long long x1=1,x2=1,y1=1,y2=1;
      |                     ^~
In file included from /usr/include/features.h:523,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/os_defines.h:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/c++config.h:683,
                 from /usr/include/c++/14/cassert:43,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:33,
                 from a.cc:1:
/usr/include/x86_64-linux-gnu/bits/mathcalls.h:257:1: note: previous declaration 'double y1(double)'
  257 | __MATHCALL (y1,, (_Mdouble_));
      | ^~~~~~~~~~
a.cc: In function 'int main()':
a.cc:22:27: error: invalid operands of types 'double(double) noexcept' and 'long long int' to binary 'operator*'
   22 |     for(i=1;i<=a;i++)y1=y1*i%Mod;
      |                         ~~^~
      |                         |  |
      |                         |  long long int
      |                         double(double) noexcept
a.cc:27:17: error: no matching function for call to 'get(double (&)(double) noexcept, long long int)'
   27 |     ans1=(x1*get(y1,Mod-2))%Mod;
      |              ~~~^~~~~~~~~~
a.cc:5:11: note: candidate: 'long long int get(long long int, long long int)' (near match)
    5 | long long get(long long x,long long y){
      |           ^~~
a.cc:5:11: note:   conversion of argument 1 would be ill-formed:
a.cc:27:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   27 |     ans1=(x1*get(y1,Mod-2))%Mod;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
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:
/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++