tree

Author: hashfx

DSA-Python/DataStructures/tree.py

@@ -0,0 +1,109 @@
+"""
+GENERAL TREE
+    Data is stored in hierarchical form
+
+                                            ROOT                                            --- Level 0
+                         ____________________|____________________
+                         A                   B                   C                          --- Level 1
+                    _____|_____         _____|_____         _____|_____
+                    |         |         |    |     |        |   |   |  |
+                    D         E         F    G     H        I   J   K  L                    --- Level 2
+               _____|_____              _____|_____
+               |   |  |  |              |         |
+               M   N  O   P             Q         R                                         --- Level 3
+
+
+
+
+         Here, ROOT is "ROOT NODE" and A, B, C are "CHILD NODE"
+            > B-D-F-G is a sub-tree
+            > B is 'ROOT NODE' for F, G, H and G is 'ROOT NODE' for Q, R
+            > Those nodes [E, F, H, I, J, K, L...] who do not have any child node are "LEAF NODE"
+            > For (D, E), A will be Ancestor and for A, (D, E) would be Descendants
+    Tree is a recursive dta structure where a child node is another tree in itself
+
+"""
+
+
+class TreeNode:
+    """ Class TreeNode """
+    def __init__(self, data):
+        self.data = data
+        self.children = []
+        self.parent = None
+
+    def add_child(self, child):
+        """ Adds children elements to Tree """
+        child.parent = self # child is an instance of class(node)
+        # adding a child node to tree
+        self.children.append(child)
+
+
+    def get_level(self):
+        """ Gets the level of Tree by counting ancestors: if a node has no ancestor, it is root node """
+        level = 0 # initialised level to 0
+        p = self.parent
+        while p:
+            """keep on going through parents and increasing levels"""
+            level += 1 # increase level by 1
+            p = p.parent
+        return level
+
+
+    def print_tree(self):
+        """Display Tree in hierarchical format"""
+        spaces = ' ' * self.get_level() * 3 # printing 3 spaces for each level
+        prefix = spaces + "|__" if self.parent else ""
+        print(prefix + self.data) # prints prefix(probably spaces) based on level
+
+        # At leaf nodes, self.children will be an empty array... so we create a check if self.children() is an empty array or not
+        if self.children: # checks if len(self.children > 0)
+            for child in self.children:
+                child.print_tree() # It will recursively call this fn and print the sub-trees
+
+
+
+
+def electronic_product():
+    root = TreeNode("Electronics")
+
+    laptop = TreeNode("Laptop")
+    laptop.add_child(TreeNode("Mac"))
+    laptop.add_child(TreeNode("Surface"))
+    laptop.add_child(TreeNode("Thinkpad"))
+
+    cellphones = TreeNode("cell Phone")
+    cellphones.add_child(TreeNode("iphone"))
+    cellphones.add_child(TreeNode("Samsung"))
+    cellphones.add_child(TreeNode("Vivo"))
+
+    tv = TreeNode("TV")
+    tv.add_child(TreeNode("Samsung"))
+    tv.add_child(TreeNode("MI"))
+
+
+    root.add_child(laptop)
+    root.add_child(cellphones)
+    root.add_child(tv)
+
+    # print(laptop.get_level()) # 1
+    # print(cellphones.get_level()) # 1
+    # print(tv.get_level()) # 1
+
+    return root
+
+
+
+
+
+# main method
+if __name__ == '__main__':
+    root = electronic_product()
+    root.print_tree() # prints tree in hierarchical format
+
+    # print(root.get_level()) # 0 // get level of root node
+
+
+
+
+