Dart DSA 🚀

A structured, interview-focused Data Structures & Algorithms roadmap in Dart, progressing from programming fundamentals to advanced problem solving.

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📌 About

This repository is a Dart-first DSA practice roadmap designed to build strong programming fundamentals and progressively prepare for coding interviews.

Dart Fundamentals
       ↓
Problem Solving
       ↓
Patterns
       ↓
Strings
       ↓
Lists / Arrays
       ↓
Set / Map / Hashing
       ↓
Recursion
       ↓
Searching & Sorting
       ↓
Stack / Queue
       ↓
Linked List
       ↓
Trees / BST
       ↓
Heap
       ↓
Graphs
       ↓
Greedy
       ↓
Dynamic Programming

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🎯 Goals

• Learn DSA using Dart
• Build strong programming fundamentals
• Solve coding problems independently
• Understand time and space complexity
• Learn common DSA patterns
• Prepare for technical coding interviews
• Write clean and optimized Dart code

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🗂️ Repository Structure

dart-dsa/
│
├── 01_dart_fundamentals/
├── 02_input_output/
├── 03_conditions/
├── 04_loops/
├── 05_functions/
├── 06_strings/
├── 07_patterns/
├── 08_lists_arrays/
├── 09_sets_maps_hashing/
├── 10_recursion/
├── 11_backtracking/
├── 12_searching/
├── 13_sorting/
├── 14_two_pointers/
├── 15_sliding_window/
├── 16_prefix_sum/
├── 17_stack/
├── 18_queue/
├── 19_linked_list/
├── 20_trees/
├── 21_bst/
├── 22_heap/
├── 23_graphs/
├── 24_greedy/
├── 25_dynamic_programming/
│
└── README.md

---

🟢 01. Dart Fundamentals

Core Topics

• main()
• Comments
• Variables
• Data Types
• var
• dynamic
• final
• const
• late
• Operators
• Type Conversion
• Null Safety

Problems

• Hello World
• Add Two Numbers
• Swap Two Numbers
• Arithmetic Operations
• Temperature Conversion
• Area of Circle
• Area of Square
• Area of Rectangle
• Simple Interest
• Compound Interest
• ASCII / Character Value

---

🟢 02. Input & Output

import 'dart:io';

void main() {
  int n = int.parse(stdin.readLineSync()!);

  print(n);
}

Important APIs

API	Purpose
stdin.readLineSync()	Read input
int.parse()	String → int
double.parse()	String → double
int.tryParse()	Safe parsing
print()	Print with newline
stdout.write()	Print without newline
stdout.writeln()	Print with newline

Problems

• Read Integer
• Read String
• Read Multiple Values
• Parse Integer
• Parse Double
• Console Calculator
• Formatted Output

---

🟢 03. Conditions

Topics

• if
• else
• else if
• Nested if
• Ternary Operator
• switch
• Logical Operators

Problems

• Even or Odd
• Positive / Negative / Zero
• Largest of Two
• Largest of Three
• Leap Year
• Vowel or Consonant
• Alphabet / Digit / Special Character
• Uppercase / Lowercase
• Voting Eligibility
• Days in Month
• Calculator Using Switch

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🟢 04. Loops

Topics

• for
• while
• do-while
• Nested Loops
• break
• continue

Problems

• Print 1 to N
• Print N to 1
• Multiplication Table
• Sum of Natural Numbers
• Sum of Even Numbers
• Sum of Odd Numbers
• Sum of Digits
• Product of Digits
• Reverse Number
• First and Last Digit
• Factorial
• Power of Number
• Prime Number
• Armstrong Number
• Palindrome Number
• Fibonacci Series
• GCD / HCF
• LCM

---

🟢 05. Functions

Topics

• Functions
• Parameters
• Return Values
• Optional Parameters
• Named Parameters
• required
• Arrow Functions
• Anonymous Functions
• Higher-Order Functions

Problems

• Prime Checker Function
• Factorial Function
• Fibonacci Function
• GCD Function
• LCM Function
• Armstrong Checker
• Palindrome Checker
• Number Conversion

---

🟡 06. Strings

Core Operations

String text = "Dart";

text.length;
text.toUpperCase();
text.toLowerCase();
text.contains("ar");
text.substring(0, 2);
text.split("");

Problems

• Reverse String
• String Palindrome
• Count Vowels
• Count Consonants
• Count Digits
• Count Special Characters
• Character Frequency
• Remove Duplicate Characters
• First Non-Repeating Character
• First Repeating Character
• Anagram
• Count Words
• Reverse Words
• Longest Word

---

🟡 07. Pattern Programming

Problems

• Square Pattern
• Rectangle Pattern
• Right Triangle
• Inverted Triangle
• Number Triangle
• Character Triangle
• Pyramid
• Inverted Pyramid
• Diamond
• Hollow Square
• Hollow Triangle
• Floyd's Triangle
• Pascal's Triangle
• Butterfly Pattern
• Numeric Palindrome Pattern
• Alphabet Pattern

Example

*
* *
* * *
* * * *
* * * * *

---

🟡 08. Lists / Arrays

Dart uses List as the primary array-like data structure.

List<int> numbers = [10, 20, 30, 40];

Problems

• Print Array
• Sum Elements
• Maximum Element
• Minimum Element
• Count Even Elements
• Count Odd Elements
• Count Negative Elements
• Reverse Array
• Find Duplicates
• Remove Duplicates
• Frequency of Elements
• Second Largest
• Second Smallest
• Left Rotation
• Right Rotation
• Merge Sorted Arrays
• Move Zeros
• Missing Number
• Duplicate Number
• Intersection
• Union

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🟡 09. Set / Map / Hashing

Set

Set<int> values = {1, 2, 3};

Map

Map<int, int> frequency = {};

for (int value in numbers) {
  frequency[value] = (frequency[value] ?? 0) + 1;
}

Problems

• Remove Duplicates
• Frequency Counting
• Two Sum
• First Unique Element
• First Repeating Element
• Intersection
• Union
• Group Anagrams
• Character Frequency
• Duplicate Detection

---

🟡 10. Recursion

Learn

• Base Case
• Recursive Case
• Call Stack
• Recursion Tree
• Complexity Analysis

Problems

• Factorial
• Fibonacci
• Sum of Numbers
• Power
• Reverse String
• Reverse Number
• Palindrome
• Array Traversal
• Maximum / Minimum
• GCD
• Binary Search

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🟠 11. Backtracking

• Generate Subsets
• Generate Permutations
• Combination Sum
• N-Queens
• Rat in a Maze
• Sudoku Solver
• Generate Parentheses

---

🟠 12. Searching

Algorithms

• Linear Search
• Binary Search

Problems

• First Occurrence
• Last Occurrence
• Lower Bound
• Upper Bound
• Search Insert Position
• Search Rotated Sorted Array
• Find Peak Element
• Square Root Using Binary Search

---

🟠 13. Sorting

Algorithm	Average	Worst
Bubble Sort	O(n²)	O(n²)
Selection Sort	O(n²)	O(n²)
Insertion Sort	O(n²)	O(n²)
Merge Sort	O(n log n)	O(n log n)
Quick Sort	O(n log n)	O(n²)
Heap Sort	O(n log n)	O(n log n)

Problems

• Bubble Sort
• Selection Sort
• Insertion Sort
• Merge Sort
• Quick Sort
• Heap Sort
• Sort 0s and 1s
• Sort 0s, 1s and 2s
• Kth Smallest
• Kth Largest

---

🔴 14. Two Pointers

• Pair With Target Sum
• Two Sum on Sorted Array
• Remove Duplicates
• Move Zeros
• Reverse Array
• Container With Most Water
• 3Sum
• 4Sum

---

🔴 15. Sliding Window

• Maximum Sum Subarray of Size K
• First Negative Number in Every Window
• Longest Substring Without Repeating Characters
• Longest Substring With K Distinct Characters
• Minimum Window Substring
• Maximum Consecutive Ones

---

🔴 16. Prefix Sum

• Running Sum
• Range Sum
• Subarray Sum
• Subarray Sum Equals K
• Equilibrium Index
• Maximum Subarray

---

🔴 17. Stack

Dart can use List as a stack:

List<int> stack = [];

stack.add(10);
stack.add(20);

int value = stack.removeLast();

Problems

• Implement Stack
• Valid Parentheses
• Reverse String
• Min Stack
• Next Greater Element
• Next Smaller Element
• Previous Greater Element
• Previous Smaller Element
• Largest Rectangle in Histogram
• Evaluate Postfix Expression

---

🔴 18. Queue

import 'dart:collection';

Queue<int> queue = Queue();

queue.add(10);
queue.add(20);

int value = queue.removeFirst();

Problems

• Implement Queue
• Circular Queue
• Stack Using Queues
• Queue Using Stacks
• First Non-Repeating Character
• Sliding Window Maximum

---

🔴 19. Linked List

Learn

• Node
• Head
• Tail
• Traversal
• Insert
• Delete
• Search
• Reverse

Problems

• Create Linked List
• Insert at Beginning
• Insert at End
• Insert at Position
• Delete Node
• Search Node
• Reverse Linked List
• Find Middle Node
• Detect Cycle
• Remove Cycle
• Merge Sorted Lists
• Remove Duplicates
• Intersection of Linked Lists

---

🔴 20. Trees

Learn

• Binary Tree
• Root
• Parent
• Child
• Leaf
• Height
• Depth
• Level

Traversals

• Preorder
• Inorder
• Postorder
• Level Order

Problems

• Tree Traversal
• Maximum Depth
• Minimum Depth
• Count Nodes
• Count Leaves
• Diameter
• Mirror Tree
• Symmetric Tree
• Lowest Common Ancestor

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🔴 21. Binary Search Tree

• Insert
• Search
• Delete
• Minimum
• Maximum
• Validate BST
• Kth Smallest
• Lowest Common Ancestor
• Sorted Array to BST

---

🔴 22. Heap / Priority Queue

Learn

• Min Heap
• Max Heap
• Heapify
• Insert
• Delete
• Priority Queue

Problems

• Kth Largest
• Kth Smallest
• Top K Frequent Elements
• Merge K Sorted Arrays
• Merge K Sorted Linked Lists
• Running Median

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🔴 23. Graphs

Representations

• Adjacency Matrix
• Adjacency List

Algorithms

• BFS
• DFS
• Connected Components
• Cycle Detection
• Topological Sort
• Dijkstra
• Bellman-Ford
• Kruskal
• Prim

Problems

• Number of Islands
• Clone Graph
• Course Schedule
• Flood Fill
• Detect Cycle
• Shortest Path
• Connected Components

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🔴 24. Greedy Algorithms

• Activity Selection
• Fractional Knapsack
• Job Sequencing
• Minimum Coins
• Jump Game
• Gas Station
• Interval Scheduling
• Merge Intervals

---

🔴 25. Dynamic Programming

Learn

• Memoization
• Tabulation
• DP State
• State Transition
• Base Cases

Problems

• Fibonacci
• Climbing Stairs
• House Robber
• 0/1 Knapsack
• Unbounded Knapsack
• Coin Change
• Longest Common Subsequence
• Longest Increasing Subsequence
• Edit Distance
• Partition Problems
• Grid DP

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🧠 Complexity Cheat Sheet

Complexity	Name
O(1)	Constant
O(log n)	Logarithmic
O(n)	Linear
O(n log n)	Linearithmic
O(n²)	Quadratic
O(2ⁿ)	Exponential
O(n!)	Factorial

Always explain both time complexity and space complexity during an interview.

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🎤 Coding Interview Workflow

For every problem:

Understand
    ↓
Identify Input / Output
    ↓
Check Edge Cases
    ↓
Brute Force
    ↓
Optimize
    ↓
Implement
    ↓
Test
    ↓
Time Complexity
    ↓
Space Complexity
    ↓
Explain

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📈 Difficulty

🟢 Easy

• Fundamentals
• Conditions
• Loops
• Basic Strings
• Basic Lists
• Basic Math

🟡 Medium

• Hashing
• Recursion
• Sorting
• Binary Search
• Two Pointers
• Sliding Window
• Stack
• Queue

🔴 Hard

• Backtracking
• Trees
• Graphs
• Heap
• Greedy
• Dynamic Programming

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✅ Progress Tracker

Dart Fundamentals

• Syntax
• Variables
• Data Types
• var
• dynamic
• final
• const
• late
• Null Safety
• Operators
• Input / Output
• Conditions
• Loops
• Functions

Core DSA

• Strings
• Patterns
• Lists
• Sets
• Maps / Hashing
• Recursion
• Backtracking
• Searching
• Sorting
• Two Pointers
• Sliding Window
• Prefix Sum

Data Structures

• Stack
• Queue
• Linked List
• Tree
• BST
• Heap
• Graph

Algorithms

• BFS
• DFS
• Binary Search
• Greedy
• Dynamic Programming

Interview Skills

• Complexity Analysis
• Edge Cases
• Brute Force → Optimized
• Dry Run
• Code Explanation
• Clean Dart Implementation

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💻 Dart DSA Template

import 'dart:io';

void main() {
  int n = int.parse(stdin.readLineSync()!);

  // Solution
}

Queue Template

import 'dart:collection';

void main() {
  Queue<int> queue = Queue();

  // Solution
}

Mathematical Problems

import 'dart:math';

void main() {
  // Solution
}

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⭐ Practice Standard

Don't measure your progress only by the number of problems solved.

For every problem, ask yourself:

Can I solve it?
      ↓
Can I explain it?
      ↓
Can I implement it in Dart?
      ↓
Can I analyze complexity?
      ↓
Can I optimize it?
      ↓
Can I solve a variation?

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🚀 Final Goal

Learn Dart
    ↓
Build Fundamentals
    ↓
Master DSA Patterns
    ↓
Solve Problems
    ↓
Analyze Complexity
    ↓
Optimize Solutions
    ↓
Practice Interviews
    ↓
Crack Coding Rounds 🚀

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⭐ Support

If this repository helps you with Dart, DSA, or interview preparation, consider giving it a ⭐.

Dart + DSA + Consistent Practice = Strong Coding Skills 🚀