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ordered lists
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‎ipython_nbs/data-structures/singly-linked-list.ipynb

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@@ -12,10 +12,10 @@
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"output_type": "stream",
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"text": [
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"Sebastian Raschka \n",
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"last updated: 2016-05-09 \n",
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"last updated: 2016-08-02 \n",
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"\n",
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"CPython 3.5.1\n",
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"IPython 4.0.3\n"
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"IPython 5.0.0\n"
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]
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}
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],
@@ -413,9 +413,9 @@
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"<__main__.SLLNode object at 0x1043b4748> [4, 5, 6]\n",
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"<__main__.SLLNode object at 0x1043b4710> [7, 8, 9]\n",
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"<__main__.SLLNode object at 0x1043b44e0> [1, 2, 3]\n"
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"<__main__.SLLNode object at 0x1047c5208> [4, 5, 6]\n",
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"<__main__.SLLNode object at 0x1047c51d0> [7, 8, 9]\n",
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"<__main__.SLLNode object at 0x1047baf98> [1, 2, 3]\n"
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]
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}
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],
@@ -594,6 +594,351 @@
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"source": [
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"So, that's basically \"Single Linked Lists\" in a nutshell!"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Ordered Lists"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"The singly-linked-list implementation above can is a so-called unordered data structure or list. The reason is that it collects items in an unsorted manner. On the other hand, ordered lists store items sorted by their values. For example, in our unordered singly-linked example, we may have a list of items in the following order:\n",
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"\n",
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"- [5, 1, 3]\n",
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"\n",
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"and and we can add items at an aribtrary position. For example, we can add a new number 4 as follows\n",
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"\n",
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"- [4, 5, 1, 3]\n",
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"- [5, 4, 1, 3]\n",
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"- [5, 1, 4, 3]\n",
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"- [5, 1, 3, 4]\n",
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"\n",
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"In an ordered list, the sorting order is always maintained. Assuming that we have an ordered list that keeps the items in ascending order, [1, 3, 5], the \"add\" method will add the number 4 only as follows:\n",
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"\n",
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"- [1, 3, 4, 5]"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 12,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class SLLNode(object):\n",
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" def __init__(self, data, next_node=None):\n",
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" self.data = data\n",
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" self.next_node = next_node\n",
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"\n",
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" \n",
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"class OrderedList(object):\n",
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" def __init__(self, head=None, datatype=int):\n",
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" self.head = head\n",
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" self.datatype = datatype\n",
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" \n",
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" def __repr__(self):\n",
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" s = ''\n",
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" if self.head is not None:\n",
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" current_node = self.head\n",
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" else:\n",
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" current_node = None\n",
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" \n",
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" while current_node is not None:\n",
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" s += ' --> %s' % current_node.data\n",
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" current_node = current_node.next_node\n",
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" return 'Size: %s\\nData: ' % self.size() + s[5:]\n",
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" \n",
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" def insert(self, data):\n",
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" if not isinstance(data, self.datatype):\n",
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" raise AttributeError('New element must have type %s' % self.datatype)\n",
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" new_node = SLLNode(data=data, next_node=None)\n",
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" \n",
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" inserted = False\n",
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" \n",
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" if self.head is None:\n",
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" print('new node')\n",
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" self.head = new_node\n",
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" inserted = True\n",
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"\n",
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" current = self.head\n",
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" previous = None\n",
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" while current is not None and not inserted:\n",
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" if current.data >= new_node.data:\n",
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" new_node.next_node = current\n",
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" if previous is not None:\n",
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" previous.next_node = new_node\n",
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" else:\n",
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" self.head = new_node\n",
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" inserted = True\n",
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" previous = current\n",
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" current = current.next_node\n",
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" \n",
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" if not inserted:\n",
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" previous.next_node = new_node\n",
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" new_node.next_node = current\n",
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" \n",
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" def size(self):\n",
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" current_node = self.head\n",
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" cnt = 0\n",
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" while current_node:\n",
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" cnt += 1\n",
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" current_node = current_node.next_node\n",
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" return cnt\n",
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" \n",
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" def search(self, data):\n",
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" current_node = self.head\n",
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" target_node = None\n",
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" while current_node is not None and target_node is None:\n",
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" if current_node.data == data:\n",
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" target_node = current_node\n",
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" else:\n",
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" current_node = current_node.next_node\n",
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" return target_node \n",
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" \n",
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" def delete(self, data):\n",
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" current_node = self.head\n",
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" previous_node = None\n",
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" found = False\n",
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"\n",
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" while current_node is not None and not found:\n",
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" if current_node.data == data:\n",
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" found = True\n",
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" if previous_node is None:\n",
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" self.head = current_node.next_node\n",
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" else:\n",
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" previous_node.next_node = current_node.next_node\n",
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" \n",
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" else:\n",
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" previous_node = current_node\n",
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" current_node = current_node.next_node"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 13,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 0\n",
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"Data: \n",
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"\n",
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"new node\n",
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"Size: 1\n",
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"Data: 1\n",
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"None\n"
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]
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}
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],
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"source": [
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"sll = OrderedList(datatype=int)\n",
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"print(sll)\n",
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"\n",
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"print()\n",
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"\n",
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"sll.insert(data=1)\n",
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"print(sll)\n",
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"print(sll.head.next_node)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 14,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 2\n",
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"Data: 1 --> 2\n"
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]
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}
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],
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"source": [
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"sll.insert(data=2)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 15,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 3\n",
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"Data: 1 --> 2 --> 2\n"
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]
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}
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],
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"source": [
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"sll.insert(data=2)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 16,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 4\n",
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"Data: 1 --> 2 --> 2 --> 3\n"
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]
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}
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],
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"source": [
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"sll.insert(data=3)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 17,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 5\n",
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"Data: 1 --> 2 --> 2 --> 3 --> 10\n"
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]
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}
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],
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"source": [
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"sll.insert(data=10)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 18,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 6\n",
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"Data: 1 --> 2 --> 2 --> 3 --> 10 --> 10\n"
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]
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}
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],
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"source": [
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"sll.insert(data=10)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 19,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 7\n",
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"Data: 1 --> 2 --> 2 --> 2 --> 3 --> 10 --> 10\n"
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]
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}
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],
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"source": [
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"sll.insert(data=2)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 20,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 8\n",
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"Data: 0 --> 1 --> 2 --> 2 --> 2 --> 3 --> 10 --> 10\n"
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]
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}
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],
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"source": [
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"sll.insert(data=0)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 21,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Size: 7\n",
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"Data: 0 --> 2 --> 2 --> 2 --> 3 --> 10 --> 10\n"
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]
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}
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],
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"source": [
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"sll.delete(data=1)\n",
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"print(sll)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 22,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"3"
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]
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},
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"execution_count": 22,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"sll.search(data=3).data"
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]
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}
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],
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"metadata": {

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