Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Sign up
Appearance settings

Commit 395387d

Browse files
Added Binary Search Tree
1 parent 658116c commit 395387d

File tree

3 files changed

+207
-2
lines changed

3 files changed

+207
-2
lines changed

‎Binary Trees/BinarySearchTree.py‎

Lines changed: 204 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,204 @@
1+
# Import the BinaryTree package from the same directory.
2+
from BinaryTree import BinaryTree, _Node
3+
4+
5+
class BST:
6+
def __init__(self):
7+
'''
8+
Initialises the root to None and creates instance of Binary Tree modules,
9+
from the BinaryTree.py file.
10+
'''
11+
self._root = None
12+
self.BT = BinaryTree()
13+
14+
def insertion_iterative(self, e):
15+
'''
16+
Inserts an item into the BST using Iterative Approach
17+
'''
18+
temp = None
19+
troot = self._root
20+
while troot:
21+
temp = troot
22+
if e < troot._element:
23+
troot = troot._left
24+
else:
25+
troot = troot._right
26+
27+
if self._root:
28+
if e < temp._element:
29+
temp._left = _Node(e)
30+
else:
31+
temp._right = _Node(e)
32+
else:
33+
self._root = _Node(e)
34+
35+
def insertion_recursive(self, troot, e):
36+
'''
37+
Inserts an item into the BST using Recursive Approach
38+
'''
39+
if troot:
40+
if e < troot._element:
41+
troot._left = self.insertion_recursive(troot._left, e)
42+
elif e > troot._element:
43+
troot._right = self.insertion_recursive(troot._right, e)
44+
else:
45+
troot = _Node(e)
46+
return troot
47+
48+
def search_iterative(self, key):
49+
'''
50+
Searches for an item in the BST using Iterative Approach
51+
'''
52+
troot = self._root
53+
while troot:
54+
if key == troot._element:
55+
return True
56+
elif key < troot._element:
57+
troot = troot._left
58+
elif key > troot._element:
59+
troot = troot._right
60+
return False
61+
62+
def search_recursive(self, troot, key):
63+
'''
64+
Searches for an item in the BST using Recursive Approach
65+
'''
66+
if troot:
67+
if key == troot._element:
68+
return True
69+
elif key < troot._element:
70+
return self.search_recursive(troot._left, key)
71+
elif key > troot._element:
72+
return self.search_recursive(troot._right, key)
73+
else:
74+
return False
75+
76+
def delete(self, key):
77+
'''
78+
Deletes an item in the BST
79+
80+
p -- reference to the node we want to delete
81+
pp -- reference to parent node of p
82+
s -- reference to the largest element in the left subtree
83+
ps -- reference to the node we want to delete (temporary)
84+
later it becomes parent to s node
85+
c -- reference to the child node
86+
'''
87+
p = self._root
88+
pp = None
89+
90+
# Finding the Node we want to delete
91+
while p and p._element != key:
92+
pp = p
93+
if key < p._element:
94+
p = p._left
95+
else:
96+
p = p._right
97+
98+
# If the Node doesn't exist in the tree.
99+
if not p:
100+
return False
101+
102+
# If the Node has both left and right sub tree.
103+
if p._left and p._right:
104+
s = p._left
105+
ps = p
106+
# Finds the largest element in the left subtree
107+
while s._right:
108+
ps = s
109+
s = s._right
110+
p._element = s._element
111+
p = s
112+
pp = ps
113+
114+
# If the node has atmost one child i.e. left child or right child
115+
# or no child (lead node)
116+
c = None
117+
if p._left:
118+
c = p._left
119+
else:
120+
c = p._right
121+
122+
if p == self._root:
123+
self._root = None
124+
else:
125+
if p == pp._left:
126+
pp._left = c
127+
else:
128+
pp._right = c
129+
130+
return True
131+
132+
def inorder(self):
133+
self.BT.inorder(self._root)
134+
135+
136+
def options():
137+
'''
138+
Prints Menu for operations
139+
'''
140+
options_list = ['Add an item (Iterative)', 'Add multiple items (Iterative)',
141+
'Add an item (Recursive)', 'Add multiple items (Recursive)',
142+
'Search (Iterative)', 'Search (Recursive)', 'Delete',
143+
'Display BST (Inorder)', 'Exit']
144+
print("\nMENU")
145+
for i, option in enumerate(options_list):
146+
print(f'{i + 1}. {option}')
147+
choice = int(input("Enter choice: "))
148+
return choice
149+
150+
151+
def switch_case(choice):
152+
'''
153+
Switch Case for operations
154+
'''
155+
# os.system('cls')
156+
if choice == 1:
157+
elem = int(input("Enter an item: "))
158+
bst.insertion_iterative(elem)
159+
160+
elif choice == 2:
161+
A = list(map(int, input("Enter numbers: ").split()))
162+
for elem in A:
163+
bst.insertion_iterative(elem)
164+
165+
elif choice == 3:
166+
elem = int(input("Enter an item: "))
167+
bst.insertion_recursive(elem)
168+
169+
elif choice == 4:
170+
A = list(map(int, input("Enter numbers: ").split()))
171+
for elem in A:
172+
bst.insertion_recursive(elem)
173+
174+
elif choice == 5:
175+
elem = int(input("Enter an item to search: "))
176+
print("Found item.") if bst.search_iterative(
177+
elem) else print("Item does not exist.")
178+
179+
elif choice == 6:
180+
elem = int(input("Enter an item to search: "))
181+
print("Found item.") if bst.search_recursive(bst._root,
182+
elem) else print("Item does not exist.")
183+
184+
elif choice == 7:
185+
elem = int(input("Enter an item to delete: "))
186+
print("Item Deleted.") if bst.delete(
187+
elem) else print("Item doesn't exist.")
188+
189+
elif choice == 8:
190+
print("Inorder Traversal:")
191+
bst.inorder()
192+
193+
elif choice == 9:
194+
import sys
195+
sys.exit()
196+
197+
###############################################################################
198+
199+
200+
if __name__ == '__main__':
201+
bst = BST()
202+
while True:
203+
choice = options()
204+
switch_case(choice)
4.52 KB
Binary file not shown.

‎README.md‎

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010

1111
Find the detailed description on [Index](Sorting%20Algorithms/) page.
1212

13-
- [Sorting Algorithms Code](Sorting%20Algorithms/sortingAlgo.py)
13+
- [Code](Sorting%20Algorithms/sortingAlgo.py)
1414
- [Random Numbers for Input](Sorting%20Algorithms/num.txt)
1515

1616
## Data Structures
@@ -35,4 +35,5 @@ Find the detailed description on operations performed [here.](Linked%20List/)
3535

3636
### 4. Binary Trees (using Linked List)
3737

38-
1. [Binary Tree](Binary%20Trees/BinaryTree.py)
38+
1. [Binary Tree](Binary%20Trees/BinaryTree.py)
39+
2. [Binary Search Tree](Binary%20Trees/BinarySearchTree.py)

0 commit comments

Comments
(0)

AltStyle によって変換されたページ (->オリジナル) /