04_recursion.ipynb

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    "### What is Recursion?\n",
    "- Any function which calls itself is called recursive.\n",
    "- It is generally shorter and easier to write than iterative code.\n",
    "- Used to perform subtasks. For example: sort, search and traversal problems.\n"
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    "# Factorial function using recursion\n",
    "\n",
    "def factorial(n):\n",
    " if n == 0:\n",
    "  return 1 \n",
    " else: return n*factorial(n-1)\n",
    "\n",
    "factorial(5)"
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    "### Recursion V/S Iteration\n",
    "\n",
    "Recursion:\n",
    "- Terminates when a base case is reached.\n",
    "- Each recursion call requires extra space on the stack frame (memory).\n",
    "- If we get infinite recursion, the problem may run out of memory and result in stack overflow.\n",
    "\n",
    "Iteration: \n",
    "- Terminates when a condition is proven to be false.\n",
    "- Each iteration doesn't require extra space.\n",
    "- Iterative solutions to a problem may not always be as obvious as a recursive solution."
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    "### Example Algorithms of Recursion\n",
    "- Fibonacci series, factorial finding\n",
    "- Merge Sort, Quick sort\n",
    "- Binary Search\n",
    "- Tree Traversal and many tree problems: In Order, PreOrder PostOrder\n",
    "- Graph traversal: DFS [Depth First Search] and BFS [Breadth First Search]\n",
    "- Dynamic Programming examples\n",
    "- Divide and conquer algorithms\n",
    "- Towers of Hanoi\n",
    "- Backtracking algorithms"
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