Depth First Traversal

Author: OmkarPathak

Programs/P64_DepthFirstTraversal.py

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+# Author: OMKAR PATHAK
+
+# Depth first search is performed in three ways:
+# Inorder
+# Preorder
+# Postorder
+
+class Node(object):
+    def __init__(self, data = None):
+        self.left = None
+        self.right = None
+        self.data = data
+
+    # for setting left node
+    def setLeft(self, node):
+        self.left = node
+
+    # for setting right node
+    def setRight(self, node):
+        self.right = node
+
+    # for getting the left node
+    def getLeft(self):
+        return self.left
+
+    # for getting right node
+    def getRight(self):
+        return self.right
+
+    # for setting data of a node
+    def setData(self, data):
+        self.data = data
+
+    # for getting data of a node
+    def getData(self):
+        return self.data
+
+
+# in this we traverse first to the leftmost node, then print its data and then traverse for rightmost node
+def inorder(Tree):
+    if Tree:
+        inorder(Tree.getLeft())
+        print(Tree.getData(), end = ' ')
+        inorder(Tree.getRight())
+    return
+
+# in this we first print the root node and then traverse towards leftmost node and then to the rightmost node
+def preorder(Tree):
+    if Tree:
+        print(Tree.getData(), end = ' ')
+        preorder(Tree.getLeft())
+        preorder(Tree.getRight())
+    return
+
+# in this we first traverse to the leftmost node and then to the rightmost node and then print the data
+def postorder(Tree):
+    if Tree:
+        postorder(Tree.getLeft())
+        postorder(Tree.getRight())
+        print(Tree.getData(), end = ' ')
+    return
+
+if __name__ == '__main__':
+    root = Node(1)
+    root.setLeft(Node(2))
+    root.setRight(Node(3))
+    root.left.setLeft(Node(4))
+
+    print('Inorder  Traversal:')
+    inorder(root)
+    print('\nPreorder Traversal:')
+    preorder(root)
+    print('\nPostorder Traversal:')
+    postorder(root)
+
+    # OUTPUT:
+    # Inorder  Traversal:
+    # 4 2 1 3
+    # Preorder Traversal:
+    # 1 2 4 3
+    # Postorder Traversal:
+    # 4 2 3 1