Binary Search Tree

Author: Shikha-code36

README.md

@@ -30,4 +30,6 @@ Data Structures and Algorithms Patterns implemented in Python.
     - [x] [Bucket Sort](Sorting-Algo/bucketsort.py)
 - [x] [Strings](Strings)
     - [x] [KMP (Knuth Morris Pratt) Pattern Searching](Strings/KMP.py)
+- [x] [Trees](Trees)
+    - [x] [Binary Search Tree](Trees/binarysearchtree.py)
 

Trees/binarysearchtree.py

@@ -0,0 +1,79 @@
+'''
+                                            Binary Search Tree
+A binary tree is a tree data structure in which each node can have a maximum of 2 children.  It means that each node in a binary tree can have either one, or two or no children. Each node in a binary tree contains data and references to its children. Both the children are named as left child and the right child according to their position.
+
+Time Complexity - O(logn)
+'''
+class BinaryTreeNode:
+    def __init__(self, data):
+        self.data = data
+        self.leftChild = None
+        self.rightChild = None
+
+
+def insert(root, newValue):
+    # if binary search tree is empty, make a new node and declare it as root
+    if root is None:
+        root = BinaryTreeNode(newValue)
+        return root
+    # binary search tree is not empty, so we will insert it into the tree
+    # if newValue is less than value of data in root, add it to left subtree and proceed recursively
+    if newValue < root.data:
+        root.leftChild = insert(root.leftChild, newValue)
+    else:
+        # if newValue is greater than value of data in root, add it to right subtree and proceed recursively
+        root.rightChild = insert(root.rightChild, newValue)
+    return root
+
+
+def search(root, value):
+    # Condition 1
+    if root == None:
+        return False
+    # Condition 2
+    elif root.data == value:
+        return True
+    # Condition 3
+    elif root.data < value:
+        return search(root.rightChild, value)
+    # Condition 4
+    else:
+        return search(root.leftChild, value)
+
+
+def findLargestElement(root):
+    # check if binary search tree is empty
+    if root == None:
+        return False
+    # check if current node is rightmost node
+    elif root.rightChild == None:
+        return root.data
+    # check right subtree of current node
+    else:
+        return findLargestElement(root.rightChild)
+
+
+root = insert(None, 15)
+
+
+def findSmallestElement(root):
+    # check if binary search tree is empty
+    if root == None:
+        return False
+    # check if current node is leftmost node
+    elif root.leftChild == None:
+        return root.data
+    # check right subtree of current node
+    else:
+        return findSmallestElement(root.leftChild)
+
+
+insert(root, 10)
+insert(root, 25)
+insert(root, 6)
+insert(root, 14)
+insert(root, 20)
+insert(root, 60)
+print(search(root, 14))  # True
+print(findLargestElement(root))  # 60
+print(findSmallestElement(root))  # 6