Added notebook solving the following: Implement a linked list with insert, find (coming soon), delete (coming soon), and print methods.

README.md

@@ -11,6 +11,10 @@ Continually updated IPython Notebooks containing algorithms and data structures.
 * [Encode spaces in a string in-place](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/arrays-strings/replace_char.ipynb)
 * [Compress a string](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/arrays-strings/compress.ipynb)
 
+## Linked Lists
+
+* [Linked list with insert, find, delete, and print methods](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/linked-lists/linked-list.ipynb)
+
 ## License
 
     Copyright 2015 Donne Martin

linked-lists/linked-list.ipynb

@@ -0,0 +1,217 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Implement a linked list with insert, find, delete, and print methods.\n",
+    "\n",
+    "* [Clarifying Questions](#Clarifying-Questions)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Pythonic-Code](#Pythonic-Code)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Clarifying Questions\n",
+    "\n",
+    "* Is this a singly or doubly linked list?\n",
+    "    * Singly\n",
+    "* Is this a circular list?\n",
+    "    * No\n",
+    "* Do we keep track of the tail or just the head?\n",
+    "    * Just the head\n",
+    "* Can you insert NULL values in the list?\n",
+    "    * No"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "### Insert to Front\n",
+    "\n",
+    "* Insert a NULL\n",
+    "* Insert in an empty list\n",
+    "* Insert in a list with one element or more elements\n",
+    "\n",
+    "### Find\n",
+    "\n",
+    "* Coming soon\n",
+    "\n",
+    "### Delete\n",
+    "\n",
+    "* Coming soon\n",
+    "\n",
+    "### Print\n",
+    "\n",
+    "* Print an empty list\n",
+    "* Print a list with one or more elements"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "### Insert to Front\n",
+    "\n",
+    "* If the data we are inserting is NULL, return\n",
+    "* Create a node with the input data\n",
+    "* If this is an empty list\n",
+    "    * Assign the head to the node\n",
+    "* Else\n",
+    "    * Set the node.next to the head\n",
+    "    * Set the head to the node\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(1)\n",
+    "* Space: O(1), a new node is added\n",
+    "\n",
+    "### Find\n",
+    "\n",
+    "* Coming soon\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n)\n",
+    "* Space: In-place\n",
+    "\n",
+    "### Delete\n",
+    "\n",
+    "* Coming soon\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n)\n",
+    "* Space: In-place\n",
+    "\n",
+    "### Print\n",
+    "\n",
+    "* For each node\n",
+    "    * Print the node's value\n",
+    "    \n",
+    "Complexity:\n",
+    "* Time: O(n)\n",
+    "* Space: In-place"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "class Node(object):\n",
+    "    def __init__(self, data):\n",
+    "        self.next = None\n",
+    "        self.data = data\n",
+    "        \n",
+    "    def __str__(self):\n",
+    "        return self.data\n",
+    "\n",
+    "class LinkedList(object):\n",
+    "    def __init__(self, head):\n",
+    "        self.head = head\n",
+    "\n",
+    "    def insert_to_front(self, data):\n",
+    "        if data is None:\n",
+    "            return\n",
+    "        node = Node(data)\n",
+    "        if self.head is None:\n",
+    "            self.head = node\n",
+    "        else:\n",
+    "            node.next = self.head\n",
+    "            self.head = node\n",
+    "\n",
+    "    def print_list(self):\n",
+    "        curr_node = self.head\n",
+    "        while curr_node is not None:\n",
+    "            print(curr_node.data)\n",
+    "            curr_node = curr_node.next"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "10\n",
+      "10\n",
+      "bc\n",
+      "a\n",
+      "10\n"
+     ]
+    }
+   ],
+   "source": [
+    "# Test insert_to_front\n",
+    "# Insert in an empty list\n",
+    "linked_list = LinkedList(None)\n",
+    "linked_list.insert_to_front(10)\n",
+    "linked_list.print_list()\n",
+    "# Insert a NULL\n",
+    "linked_list.insert_to_front(None)\n",
+    "linked_list.print_list()\n",
+    "# Insert in a list with one element or more elements\n",
+    "linked_list.insert_to_front('a')\n",
+    "linked_list.insert_to_front('bc')\n",
+    "linked_list.print_list()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "# Test empty print\n",
+    "linked_list = LinkedList(None)\n",
+    "linked_list.print_list()"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}