Language: C++

#include<bits/stdc++.h>
#define R(n)for(L i=0;i<n;i++)
#define M make_pair
using L long long;
using namespace std;
int main(){
    L n,k,s,t,a[50];cin>>n>>k>>s>>t;
    R(n)cin>>a[i];
    map<pair<L,L>,L> p[50];
    R(n){
        for(L j=k-2;j+1;j--)for(const auto&l:p[j])p[j+1][M(l.first.first&a[i],l.first.second|a[i])]+=l.second;
        p[0][M(a[i],a[i])]=1;
    }
    n=0;
    R(k)n+=p[i][M(s,t)];
    cout<<n;
}

Compiler output:
a.cc:4:7: error: expected nested-name-specifier before 'L'
    4 | using L long long;
      |       ^
a.cc: In function 'int main()':
a.cc:7:5: error: 'L' was not declared in this scope
    7 |     L n,k,s,t,a[50];cin>>n>>k>>s>>t;
      |     ^
a.cc:7:26: error: 'n' was not declared in this scope; did you mean 'yn'?
    7 |     L n,k,s,t,a[50];cin>>n>>k>>s>>t;
      |                          ^
      |                          yn
a.cc:7:29: error: 'k' was not declared in this scope
    7 |     L n,k,s,t,a[50];cin>>n>>k>>s>>t;
      |                             ^
a.cc:7:32: error: 's' was not declared in this scope
    7 |     L n,k,s,t,a[50];cin>>n>>k>>s>>t;
      |                                ^
a.cc:7:35: error: 't' was not declared in this scope; did you mean 'tm'?
    7 |     L n,k,s,t,a[50];cin>>n>>k>>s>>t;
      |                                   ^
      |                                   tm
a.cc:2:19: error: expected ';' before 'i'
    2 | #define R(n)for(L i=0;i<n;i++)
      |                   ^
a.cc:8:5: note: in expansion of macro 'R'
    8 |     R(n)cin>>a[i];
      |     ^
a.cc:2:23: error: 'i' was not declared in this scope
    2 | #define R(n)for(L i=0;i<n;i++)
      |                       ^
a.cc:8:5: note: in expansion of macro 'R'
    8 |     R(n)cin>>a[i];
      |     ^
a.cc:8:14: error: 'a' was not declared in this scope
    8 |     R(n)cin>>a[i];
      |              ^
a.cc:9:20: error: template argument 1 is invalid
    9 |     map<pair<L,L>,L> p[50];
      |                    ^
a.cc:9:20: error: template argument 3 is invalid
a.cc:9:20: error: template argument 4 is invalid
a.cc:2:19: error: expected ';' before 'i'
    2 | #define R(n)for(L i=0;i<n;i++)
      |                   ^
a.cc:10:5: note: in expansion of macro 'R'
   10 |     R(n){
      |     ^
a.cc:2:23: error: 'i' was not declared in this scope
    2 | #define R(n)for(L i=0;i<n;i++)
      |                       ^
a.cc:10:5: note: in expansion of macro 'R'
   10 |     R(n){
      |     ^
a.cc:11:14: error: expected ';' before 'j'
   11 |         for(L j=k-2;j+1;j--)for(const auto&l:p[j])p[j+1][M(l.first.first&a[i],l.first.second|a[i])]+=l.second;
      |              ^~
      |              ;
a.cc:11:21: error: 'j' was not declared in this scope
   11 |         for(L j=k-2;j+1;j--)for(const auto&l:p[j])p[j+1][M(l.first.first&a[i],l.first.second|a[i])]+=l.second;
      |                     ^
a.cc:11:74: error: 'a' was not declared in this scope
   11 |         for(L j=k-2;j+1;j--)for(const auto&l:p[j])p[j+1][M(l.first.first&a[i],l.first.second|a[i])]+=l.second;
      |                                                                          ^
a.cc:12:16: error: 'a' was not declared in this scope
   12 |         p[0][M(a[i],a[i])]=1;
      |                ^
a.cc:2:19: error: expected ';' before 'i'
    2 | #define R(n)for(L i=0;i<n;i++)
      |                   ^
a.cc:15:5: note: in expansion of macro 'R'
   15 |     R(k)n+=p[i][M(s,t)];
      |     ^
a.cc:2:23: error: 'i' was not declared in this scope
    2 | #define R(n)for(L i=0;i<n;i++)
      |                       ^
a.cc:15:5: note: in expansion of macro 'R'
   15 |     R(k)n+=p[i][M(s,t)];
      |     ^