Data Structures in Dart

 

📚 Data Structures in Dart – With Examples, Uses & Practice Problems

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🔍 Introduction

Data Structures are the foundation of programming and problem-solving. Dart, being a modern language used in Flutter and backend apps, supports all key data structures you need to build efficient software.

Whether you're building a quiz app, a shopping cart, or a chat system, using the right data structure can:

• Save memory 🧠

• Improve performance ⚡

• Make your code easy to maintain 💡

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📦 List of Common Data Structures in Dart

Data Structure	Type	Example Use Case
List	Linear	Storing names, items, scores
Set	Unordered	Unique tags, categories
Map	Key-Value Pair	Storing user info, product prices
Queue	FIFO	Task scheduling, printer queue
Stack	LIFO	Undo/redo, browser history
LinkedList	Linked Nodes	Custom memory-efficient storage
PriorityQueue	Ordered Queue	Job scheduling, AI search

Let’s explore them one by one with examples 👇

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1️⃣ List (Ordered Collection)

void main() {
  List<String> names = ['Aman', 'Riya', 'Rohan'];
  names.add('Nita');
  print(names); // Output: [Aman, Riya, Rohan, Nita]
}

Use cases:

• Scores in a game

• User comments

• Student names

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2️⃣ Set (Unordered and Unique)

void main() {
  Set<int> numbers = {1, 2, 3, 3};
  print(numbers); // Output: {1, 2, 3}
}

Use cases:

• Removing duplicates

• Tags, filters

• Fast lookup of unique items

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3️⃣ Map (Key-Value Pairs)

void main() {
  Map<String, int> marks = {'Math': 90, 'Science': 80};
  print(marks['Math']); // Output: 90
}

Use cases:

• User profile (name, age, email)

• Product (name → price)

• Lookup tables

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4️⃣ Queue (First In, First Out)

import 'dart:collection';
void main() {
  Queue<String> queue = Queue();
  queue.add('Task1');
  queue.add('Task2');
  print(queue.removeFirst()); // Task1
}

Use cases:

• Task management

• Event queues

• Messaging systems

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5️⃣ Stack (Last In, First Out)

void main() {
  List<String> stack = [];
  stack.add('Page1');
  stack.add('Page2');
  print(stack.removeLast()); // Page2
}

Use cases:

• Undo/redo

• Backtracking

• Reversing things

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6️⃣ LinkedList (Doubly Linked)

import 'dart:collection';
void main() {
  final list = LinkedList<Entry>();
  list.addAll([Entry('A'), Entry('B')]);
  list.forEach((e) => print(e.name));
}
class Entry extends LinkedListEntry<Entry> {
  String name;
  Entry(this.name);
}

Use cases:

• Custom memory-efficient collections

• Insertion-heavy operations

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7️⃣ PriorityQueue (From collection package)

import 'package:collection/collection.dart';
void main() {
  var queue = PriorityQueue<int>((a, b) => b.compareTo(a));
  queue.addAll([5, 1, 10]);
  print(queue.removeFirst()); // 10
}

Use cases:

• Scheduling algorithms

• Game AI (pathfinding)

• Huffman encoding

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🌟 Why Learn These in Dart?

• 📱 Used in Flutter apps (e.g., list of widgets, user inputs)

• 💾 Backend apps (chat queue, login sessions, product catalogs)

• 🧠 Core for DSA Interviews and Competitive Coding

• 🔁 Help in managing real-time state & data flow

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❓ Unsolved Problems (Practice Time!)

1. Create a List to store daily temperatures and find the average.

2. Take a list of numbers and remove duplicates using Set.

3. Build a Map to store student names and their marks, then print the topper.

4. Simulate a queue of people entering a bus using Queue.

5. Implement a calculator that uses a Stack to reverse a string.

6. Create a to-do list manager using a PriorityQueue (task with higher priority first).

7. Create your own linked list of names using LinkedList.

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🧾 Summary

Structure	Ordered	Unique	Fast Lookup	Best For
List	✅	❌	✅	Ordered items, basic arrays
Set	❌	✅	✅	Unique items, filters
Map	✅	Keys	✅	Key-value storage
Queue	✅	❌	❌	First-in-first-out processing
Stack	✅	❌	❌	Backtracking, undo/redo
LinkedList	✅	❌	❌	Custom nodes, fast inserts
PriorityQueue	✅	❌	✅	Sorted dynamic processing

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✍️ Final Words

Dart gives you all the tools to build fast, flexible, and intelligent apps — only if you master data structures.

Practice. Refactor. Solve Real Problems. That’s how you grow as a Dart & Flutter developer 💪

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