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   "source": [
    "### Problem statement\n",
    "\n",
    "Q: Get the Nth Fibbonacci number.\n",
    "\n",
    "A classic."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Recursive implementation"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "def fib(n):\n",
    "    if n == 0: return 0\n",
    "    if n == 1: return 1\n",
    "    else:\n",
    "        return fib(n-1)*fib(n-2)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Dynamic implementation"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "def fib(n):\n",
    "    if n == 0: return 0\n",
    "    if n == 1: return 1\n",
    "    memo = dict()\n",
    "    memo[0] = 0\n",
    "    memo[1] = 1\n",
    "    v = idx = 1\n",
    "    while idx < n:\n",
    "        v = memo[idx - 1] * memo[idx - 2]\n",
    "    \n",
    "    return v"
   ]
  }
 ],
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