Trie Node Design and Initialization in DSA Typescript - Execution Trace

Concept Flow - Trie Node Design and Initialization

Create TrieNode class

↓

Initialize children map/dictionary

↓

Set isEndOfWord flag to false

↓

Ready to use node in Trie structure

This flow shows how a Trie node is created with a children map and a flag to mark word endings.

Execution Sample

DSA Typescript

class TrieNode {
  children: Map<string, TrieNode>;
  isEndOfWord: boolean;

  constructor() {
    this.children = new Map();
    this.isEndOfWord = false;
  }
}

Defines a TrieNode class with a map for children nodes and a boolean flag to mark the end of a word.

Execution Table

Step	Operation	Children Map State	isEndOfWord	Visual State
1	Create new TrieNode instance	{}	false	TrieNode { children: Map(0) {}, isEndOfWord: false }
2	Initialize children as empty Map	{}	false	TrieNode { children: Map(0) {}, isEndOfWord: false }
3	Set isEndOfWord to false	{}	false	TrieNode { children: Map(0) {}, isEndOfWord: false }
4	Node ready for insertion in Trie	{}	false	TrieNode { children: Map(0) {}, isEndOfWord: false }

💡 Initialization complete; node is empty with no children and not marking end of word.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
children	undefined	Map(0) {}	Map(0) {}	Map(0) {}	Map(0) {}
isEndOfWord	undefined	undefined	undefined	false	false

Key Moments - 3 Insights

Why is children initialized as an empty Map instead of an array or object?

Using a Map allows efficient insertion and lookup of child nodes by character keys, as shown in execution_table step 2 where children is set to an empty Map {}.

Why is isEndOfWord set to false initially?

Because when a node is created, it does not yet represent the end of any word. This is confirmed in execution_table step 3 where isEndOfWord is set to false.

What does the visual state represent after initialization?

It shows the node has no children and does not mark the end of a word, matching the empty children map and false flag in execution_table rows.

Visual Quiz - 3 Questions

Look at the execution_table, what is the state of children after step 2?

A undefined

B {} (empty Map)

C null

D Array with one element

💡 Hint

Check the 'Children Map State' column at step 2 in execution_table.

At which step is isEndOfWord set to false?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'isEndOfWord' column in execution_table to find when it changes.

If we did not initialize children as an empty Map, what would happen when inserting a child node?

A Insertion would fail because children is undefined

B Insertion would work normally

C isEndOfWord would become true automatically

D The node would delete itself

💡 Hint

Refer to variable_tracker for children variable state before initialization.

Concept Snapshot

TrieNode Design:
- children: Map<string, TrieNode> to hold child nodes
- isEndOfWord: boolean flag for word end
- Initialize children as empty Map
- Set isEndOfWord to false
- Ready for Trie insertion

Full Transcript

We create a TrieNode class with two main parts: a children map to hold links to next nodes, and a boolean flag isEndOfWord to mark if the node ends a word. Initially, children is empty and isEndOfWord is false. This setup allows us to build a Trie by adding child nodes for each character and marking word ends. The execution table shows each step of initialization, confirming the node starts empty and not marking any word end. This design supports efficient Trie operations like insert and search.