title: Hypercube Graph
signature: hypercube_graph <- function(n) {
test_code: 
  
  
  # SOLUTION CODE
  # ============================================
  PLACEHOLDER_CODE_BODY
  
  # TESTING CODE 
  # ============================================
  validate_solution <- function(actual, expected) {
      toString(actual)==toString(expected)
  }
  
  driver <- function(n, expected){
      if (validate_solution(PLACEHOLDER_FN_NAME(n), expected)){
          "PASSED"
      } else{
          "FAILED"
      }
  }
  
  main <- function() {
      cat(sprintf("TEST-0...%s\n",driver(
          28L, 
          268435456L
      )))
  
      cat(sprintf("TEST-1...%s\n",driver(
          45L, 
          35184372088832L
      )))
  
      cat(sprintf("TEST-2...%s\n",driver(
          41L, 
          2199023255552L
      )))
  
      cat(sprintf("TEST-3...%s\n",driver(
          36L, 
          68719476736L
      )))
  
  }
  
  main()
source_py: def hypercube_graph(n):
      if (n == 1):
          return 2
      return (2 * hypercube_graph((n - 1)))
source_cpp: int hypercube_graph(int n) {
    if ( n == 1 ) return 2;
    return 2 * hypercube_graph ( n - 1 );
  }