feat: implement OBST

Author: erikgreasy

.gitignore

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+__pycache__

Node.py

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+class Node:
+    def __init__(self, value, word):
+        self.value = value
+        self.word = word
+        self.left = None
+        self.right = None
+
+    def __repr__(self):
+        """Use word property when trying to print Node class"""
+
+        return self.word

buildTree.py

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+from Node import Node
+
+
+def buildTree(root_table, n, words):
+    """Create nodes of the OBST based on the root table"""
+    
+    root_ = root_table[1][n]
+
+    root_node = Node(root_, words[root_])
+    s = []
+
+    s.append((root_node, 1, n))
+
+    while(len(s) != 0):
+        (u, i, j) = s.pop()
+        l = root_table[i][j]
+
+        if l < j:
+            # build the right tree
+            v = Node(root_table[l+1][j], words[root_table[l+1][j]])
+            u.right = v
+            s.append((v, l+1, j))
+        if i < l:
+            # build left subtree
+            v = Node(root_table[i][l-1], words[root_table[i][l-1]])
+            u.left = v
+            s.append((v, i, l-1))
+
+    return root_node