a c++ performance test for dynamic programming fibonacci calculations vs naive recursive calculations

dynamic_fib.cpp

#include <iostream>
using std::cout;
using std::cin;
using std::endl;

#include <ctime>
using std::clock_t;

#include <map>
using std::map;

// segfaults when calculating 130954
int _dp_fib_helper(int n, map<int, int>* memo) {
  if((*memo).count(n)) {
    return (*memo)[n];
  }
  int f;
  (n <= 2) ? f = 1 : f = _dp_fib_helper(n - 1, memo) + _dp_fib_helper(n - 2, memo);
  (*memo)[n] = f;

  return f;
}

int dp_fib(int n) {
  map<int,int>* memo = new map<int,int>();
  int f = _dp_fib_helper(n, memo);
  delete(memo);
  return f;
}

int fib(int n) {
  if(n <= 2) {
    return 1;
  } else {
    return fib(n - 1) + fib(n - 2);
  }
}

int main() {

  int n = 0;
  int f = 0;
  double elapsed_secs = 0;

  /* NAIVE FIBONACCI */
  cout << "Enter an int for regular fib:" << endl;
  cin >> n;

  clock_t begin = clock();
  f = fib(n);
  clock_t end = clock();
  elapsed_secs = double(end - begin) / CLOCKS_PER_SEC;

  cout << "FIB:\t" << f << "\tTIME:\t" << elapsed_secs << endl;

  /* DP FIBONACCI */
  cout << "\nEnter an int for dynamic programming fib:" << endl;
  cin >> n;

  begin = clock();
  f = dp_fib(n);
  end = clock();
  elapsed_secs = double(end - begin) / CLOCKS_PER_SEC;

  cout << "FIB:\t" << f << "\tTIME:\t" << elapsed_secs << endl;
  return 0;
}