Added binary tree implementation

Author: OmkarPathak

pygorithm/data_structures/tree.py

@@ -0,0 +1,83 @@
+# Author: OMKAR PATHAK
+# Created On: 9th August 2017
+
+# Node class to create a node for binary tree
+class Node(object):
+    def __init__(self, data = None):
+        self.left = None
+        self.right = None
+        self.data = data
+
+    # for setting left node
+    def set_left(self, node):
+        self.left = node
+
+    # for setting right node
+    def set_right(self, node):
+        self.right = node
+
+    # for getting the left node
+    def get_left(self):
+        return self.left
+
+    # for getting right node
+    def get_right(self):
+        return self.right
+
+    # for setting data of a node
+    def set_data(self, data):
+        self.data = data
+
+    # for getting data of a node
+    def get_data(self):
+        return self.data
+
+    # easily retrieve the source code of the Node class
+    def get_code(self):
+        import inspect
+        return inspect.getsource(Node)
+
+# BinaryTree class to create a binary tree
+class BinaryTree(object):
+    def __init__(self):
+        self._inorder = []
+        self._preorder = []
+        self._postorder = []
+
+    # in this we traverse first to the leftmost node, then print its data and then traverse for rightmost node
+    def inorder(self, root):
+        '''
+        @type: root:   Node object
+        '''
+        if root:
+            self.inorder(root.get_left())                # traverse to leftmost child
+            self._inorder.append(root.get_data())    # get the data of current node
+            self.inorder(root.get_right())               # traverse to rightmost child
+        return self._inorder
+
+    # in this we first print the root node and then traverse towards leftmost node and then to the rightmost node
+    def preorder(self, root):
+        '''
+        @type: root:   Node object
+        '''
+        if root:
+            self._preorder.append(root.get_data())   # get the data of current node
+            self.preorder(root.get_left())               # traverse to leftmost child
+            self.preorder(root.get_right())              # traverse to rightmost child
+        return self._preorder
+
+    # in this we first traverse to the leftmost node and then to the rightmost node and then print the data
+    def postorder(self, root):
+        '''
+        @type: root:   Node object
+        '''
+        if root:
+            self.postorder(root.get_left())              # traverse to leftmost child
+            self.postorder(root.get_right())             # traverse to rightmost child
+            self._postorder.append(root.get_data())  # get the data of current node
+        return self._postorder
+
+    # easily retrieve the source code of the BinaryTree class
+    def get_code(self):
+        import inspect
+        return inspect.getsource(BinaryTree)