1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
|
{
"metadata": {
"name": "",
"signature": "sha256:8af7b49cf811d590bd7b25dd4e6ee061b1b9e37ea11f5e8572f545bc4780f1b4"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 8 : Binary Trees"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Exmaple 8.1 Page No : 406"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"# for Stack class\n",
"class Node:\n",
" def __init__(self):\n",
" self.iData = None # data item (key)\n",
" self.dData = None # data item\n",
" self.leftChild = None # this nodes left child\n",
" self.rightChild = None # this nodes right child\n",
"\n",
" def displayNode(self):\n",
" # display ourself\n",
" print '{' , self.iData , ',' ,self.dData , '}',\n",
"\n",
"class Tree:\n",
" def __init__(self):\n",
" # constructor\n",
" self.root = None # no nodes in tree \n",
"\n",
" def find(self,key): # find node with given key\n",
" # (assumes non-empty tree)\n",
" current = self.root # start at self.root\n",
" while(current.iData != key): # while no match,\n",
" if(key < current.iData): # go left?\n",
" current = current.leftChild\n",
" else: # or go right?\n",
" current = current.rightChild\n",
" if(current == None): # if no child,\n",
" return None # didnt find it\n",
" return current\n",
"\n",
" def insert(self,i,dd):\n",
" newNode = Node() # make new node\n",
" newNode.iData = i # insert data\n",
" newNode.dData = dd\n",
" if(self.root==None):# no node in self.root\n",
" self.root = newNode\n",
" else: # self.root occupied\n",
" current = self.root # start at self.root\n",
" while(True): # (exits internally)\n",
" parent = current\n",
" if(i < current.iData): # go left?\n",
" current = current.leftChild\n",
" if(current == None): # if end of the line,\n",
" # insert on left\n",
" parent.leftChild = newNode\n",
" return\n",
" else:# or go right?\n",
" current = current.rightChild\n",
" if(current == None): # if end of the line \n",
" # insert on right\n",
" parent.rightChild = newNode\n",
" return\n",
"\n",
" def delete(self,key): # delete node with given key\n",
" # (assumes non-empty list)\n",
" current = self.root\n",
" parent = self.root\n",
" isLeftChild = True\n",
" while(current.iData != key):\n",
" parent = current\n",
" if(key < current.iData):\n",
" isLeftChild = True\n",
" current = current.leftChild\n",
" else:\n",
" isLeftChild = False\n",
" current = current.rightChild\n",
" if(current == None):\n",
" return False\n",
" # if no children, simply delete it\n",
" if(current.leftChild==None and current.rightChild==None):\n",
" if(current == self.root): # if self.root,\n",
" self.root = None # tree is empty\n",
" elif(isLeftChild):\n",
" parent.leftChild = None\n",
" else:\n",
" parent.rightChild = None\n",
"\n",
" elif(current.rightChild==None):\n",
" if(current == self.root):\n",
" self.root = current.leftChild\n",
" elif(isLeftChild):\n",
" parent.leftChild = current.leftChild\n",
" else:\n",
" parent.rightChild = current.leftChild # if no left child, replace with right subtree\n",
" elif(current.leftChild==None):\n",
" if(current == self.root):\n",
" self.root = current.rightChild\n",
" elif(isLeftChild):\n",
" parent.leftChild = current.rightChild\n",
" else:\n",
" parent.rightChild = current.rightChild\n",
" else: # two children, so replace with inorder successor\n",
" # get successor of node to delete (current)\n",
" successor = self.getSuccessor(current)\n",
" # connect parent of current to successor instead\n",
" if(current == self.root):\n",
" self.root = successor\n",
" elif(isLeftChild):\n",
" parent.leftChild = successor\n",
" else:\n",
" parent.rightChild = successor\n",
" # connect successor to currents left child\n",
" successor.leftChild = current.leftChild\n",
" return True\n",
"\n",
" def getSuccessor(self,delNode):\n",
" successorParent = delNode\n",
" successor = delNode\n",
" current = delNode.rightChild # go to right child\n",
" while(current != None): # until no more\n",
" # left children,\n",
" successorParent = successor\n",
" successor = current\n",
" current = current.leftChild # go to left child\n",
" # if successor not\n",
" if(successor != delNode.rightChild): # right child,\n",
" # make connections\n",
" successorParent.leftChild = successor.rightChild\n",
" successor.rightChild = delNode.rightChild\n",
" return successor\n",
"\n",
" def traverse(self,traverseType):\n",
" if traverseType == 1:\n",
" print '\\nPreorder traversal: ',\n",
" self.preOrder(self.root)\n",
" elif traverseType == 2:\n",
" print '\\nInorder traversal: ',\n",
" self.inOrder(self.root)\n",
" else:\n",
" print '\\nPostorder traversal: ',\n",
" self.postOrder(self.root)\n",
" print ''\n",
"\n",
" def preOrder(self, localroot):\n",
" if(localroot != None):\n",
" print localroot.iData ,\n",
" self.preOrder(localroot.leftChild)\n",
" self.preOrder(localroot.rightChild)\n",
"\n",
" def inOrder(self, localroot):\n",
" if(localroot != None):\n",
" self.inOrder(localroot.leftChild)\n",
" print localroot.iData ,\n",
" self.inOrder(localroot.rightChild)\n",
" \n",
" def postOrder(self, localroot):\n",
" if(localroot != None):\n",
" self.postOrder(localroot.leftChild)\n",
" self.postOrder(localroot.rightChild)\n",
" print localroot.iData ,\n",
"\n",
" def displayTree(self):\n",
" globalStack = list()\n",
" globalStack.append(self.root)\n",
" nBlanks = 32\n",
" isRowEmpty = False\n",
" print '\\n......................................................'\n",
" while(isRowEmpty==False):\n",
" localStack = list()\n",
" isRowEmpty = True\n",
" for j in range(nBlanks):\n",
" print ' ',\n",
" while(globalStack is not None):\n",
" temp = globalStack.pop()\n",
" if(temp != None):\n",
" print temp.iData,\n",
" localStack.append(temp.leftChild)\n",
" localStack.append(temp.rightChild)\n",
" if(temp.leftChild != None or temp.rightChild != None):\n",
" isRowEmpty = False\n",
" else:\n",
" print '--' ,\n",
" localStack.push(None)\n",
" localStack.push(None)\n",
" for j in range(nBlanks*2-2):\n",
" print ' ', # end while globalStack not empty\n",
" \n",
" print ''\n",
" nBlanks /= 2\n",
" while(localStack is not None):\n",
" globalStack.append( localStack.pop() ) # end while isRowEmpty is false\n",
" \n",
" print '\\n......................................................'\n",
"\n",
"theTree = Tree()\n",
"theTree.insert(50,1.5)\n",
"theTree.insert(25,1.2)\n",
"theTree.insert(75,1.7)\n",
"theTree.insert(12,1.5)\n",
"theTree.insert(37,1.2)\n",
"theTree.insert(43,1.7)\n",
"theTree.insert(30,1.5)\n",
"theTree.insert(33,1.2)\n",
"theTree.insert(87,1.7)\n",
"theTree.insert(93,1.5)\n",
"theTree.insert(97,1.5)\n",
"while(True):\n",
" print 'Enter first letter of show, '\n",
" print 'insert, find, delete, or traverse: ',\n",
" choice = raw_input()\n",
" if choice == 's':\n",
" theTree.displayTree()\n",
" elif choice == 'i':\n",
" print 'Enter value to insert: '\n",
" value = int(raw_input())\n",
" theTree.insert(value, value + 0.9)\n",
" elif choice == 'f':\n",
" print 'Enter value to find: ',\n",
" value = int(raw_input())\n",
" found = theTree.find(value)\n",
" if(found != None):\n",
" print 'Found: ', \n",
" found.displayNode()\n",
" print ''\n",
" else:\n",
" print 'Could not find', value \n",
" elif choice=='d':\n",
" print 'Enter value to delete: ',\n",
" value = int(raw_input())\n",
" didDelete = theTree.delete(value)\n",
" if(didDelete):\n",
" print 'Deleted ' , value \n",
" else:\n",
" print 'Could not delete ',value\n",
" elif choice=='t':\n",
" print 'Enter type 1, 2 or 3: '\n",
" value = int(raw_input())\n",
" theTree.traverse(value)\n",
" else:\n",
" print 'Invalid entry'\n"
],
"language": "python",
"metadata": {},
"outputs": []
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
