Create trie.py

Author: careermonk

src/chapter06trees/trie.py

@@ -0,0 +1,76 @@
+# Copyright (c) Feb 26, 2021 CareerMonk Publications and others.
+# E-Mail           		: info@careermonk.com 
+# Creation Date    		: 2021-02-26 06:15:46 
+# Last modification		: 2021-02-26 
+#               by		: Narasimha Karumanchi 
+# Book Title			: Data Structures And Algorithmic Thinking With Python
+# Warranty         		: This software is provided "as is" without any 
+# 				   warranty; without even the implied warranty of 
+# 				    merchantability or fitness for a particular purpose. 
+
+class TrieNode:
+    def __init__(self):
+        self.children = dict()
+        self.isLeaf = False
+    
+    def insert(self, word):
+        current = self
+        for char in word:
+            if char not in current.children:
+                current.children[char] = TrieNode()
+            current = current.children[char]
+        current.isLeaf = True
+        
+    def search(self, word):
+        current = self
+        for char in word:
+            if char not in current.children:
+                return False
+            current = current.children[char]
+        return current.isLeaf
+    
+    def wordsWithPrefix(self, prefix):
+        current = self
+        result = []
+        
+        def printer(current, path, result):
+            if current.isLeaf == True:
+                result.append(path)
+                
+            for child in current.children:
+                printer(current.children[child], path + child, result)
+        
+        for char in prefix:
+            if char not in current.children:
+                return result
+            current = current.children[char]
+            
+        printer(current, prefix, result)
+        return result
+    
+    def printWords(self):
+        current = self
+        result = []
+        def printer(current, path, result):
+            if current.isLeaf == True:
+                result.append(path)
+                
+            for child in current.children:
+                printer(current.children[child], path + child, result)
+        
+        printer(current, "", result)
+        return result
+    
+    
+words = "banana bananas bandana band apple all beast"
+
+root = TrieNode()
+for word in words.split(" "):
+    root.insert(word)
+
+for word in words.split(" "):
+    print(root.search(word))
+    
+print(root.printWords())
+
+print(root.wordsWithPrefix("a"))