foo.cpp:10:18: error: invalid suffix "n" on integer constant
  for(int i=1; i<=2n-1; ++i){
                  ^
foo.cpp:28:10: error: invalid suffix "n" on integer constant
  cout<<f[2n-1][n][n][n]<<endl;
          ^
foo.cpp:1:1: error: 'include' does not name a type
 include <iostream>
 ^
foo.cpp: In function 'int main()':
foo.cpp:6:2: error: 'cin' was not declared in this scope
  cin>>n;
  ^
foo.cpp:11:25: error: 'min' was not declared in this scope
  for(int j=1; j<=min(i,n); ++j){
                         ^
foo.cpp:23:57: error: 'max' was not declared in this scope
  f[i][j][k][x]=max(f[i][j][k][x],f[i-1][j-q][k-w][x-e]+c);
                                                         ^
foo.cpp:28:2: error: 'cout' was not declared in this scope
  cout<<f[2n-1][n][n][n]<<endl;
  ^
foo.cpp:28:26: error: 'endl' was not declared in this scope
  cout<<f[2n-1][n][n][n]<<endl;
                          ^