Binääripuu

input/code.cpp: In function 'int main()':
input/code.cpp:58:2: error: jump to label 'res' [-fpermissive]
  res:
  ^~~
input/code.cpp:22:41: note:   from here
   if(m == 0) { sv = n-2; so = n-2; goto res;}
                                         ^~~
input/code.cpp:33:8: note:   crosses initialization of 'long int pro'
   long pro = 0;
        ^~~
input/code.cpp:32:8: note:   crosses initialization of 'bool inte'
   bool inte = false;
        ^~~~
input/code.cpp:31:8: note:   crosses initialization of 'long int it'
   long it = 2;
        ^~
input/code.cpp:30:7: note:   crosses initialization of 'int k'
   int k = 1;
       ^
input/code.cpp:24:13: note:   crosses initialization of 'std::set<long int> fb'
   set<long> fb;
             ^~

#include<bits/stdc++.h>
using namespace std;

long long M = 1e9+7;

long long pw(long long x, long long n) {
  if(n == 1) return x;
  if(n == 0) return 1;
  if(n%2==0) {
    long long bb = pw(x,n/2);
    return (bb*bb)%M;
  }
  else {
    return ((pw(x,n-1)*x)%M);
  }
}

int main() {
  int n,m;cin>>n>>m;
  long long sv; long long so;
  sv = 0; so = 0;
  if(m == 0) { sv = n-2; so = n-2; goto res;}
  bool kr[1010101];
  set<long> fb; 
  kr[1] = true;
  for(int i = 0; i < m; i++) {
    long a; cin >> a;
    fb.insert(a);
  }
  int k = 1;
  long it = 2;
  bool inte = false;
  long pro = 0;
  while(k < n) {
    if(k == n-1 && !inte) pro = it;
    long kk = pw(2,k);
    for(int i = 0; i < kk; i++) {
      if(fb.count(it)) kr[i] = false;
      else {
	kr[it] = kr[it/2];
      }
      it++;
    }
    k++;
  }
  //cout << "\n";
  
  for(int i = pro; i < pro+pro/2; i++) {
    if(kr[i]) sv++;
    //cout << kr[i] << " ";
  }
  for(int i = pro+pro/2; i < 2*pro; i++) {
    if(kr[i]) so++;
    //cout << kr[i] << " ";
  }
  //cout << endl;
  //cout << sv << " :: " << so << "\n";
 res:
  cout << (((sv*so)%M)*2)%M;
}