💻 DSA Journey (Day-by-Day Progress)

📅 Day 1: Input & Output + Conditional Statements

Topics Covered:

• Taking input from the user
• Displaying output
• Conditional statements (if, else, else if)

📅 Day 2: Loops + Prime Number Logic

Topics Covered:

• Loops: for, while, and do-while
• Prime number checking
• Prime numbers printing till the given number

📅 Day 3: Fibonacci Series

🧠 Topic: Fibonacci Series Generation
📥 Input: Number of terms to print (provided by the user)
📤 Output: A sequence of Fibonacci numbers up to the given number of terms

📅 Day 4: Digit Count & Reverse of a Number

🧠 Topic: Number Digit Count and Reversal
📥 Input: A positive integer (entered by the user)
📤 Output:

• Total number of digits in the number
• Reverse of the number

📅 Day 5: GCD and LCM of Two Numbers

🧠 Topic: Greatest Common Divisor (GCD) & Least Common Multiple (LCM)
📥 Input: Two positive integers (entered by the user)
📤 Output:

• GCD of the two numbers
• LCM of the two numbers

📅 Day 6: Prime Factorization of a Number

🧠 Topic: Prime Factorization
📥 Input: A positive integer (entered by the user)
📤 Output: All prime factors of the given number

📅 Day 7: Right-Angled Triangle Check & Area Calculation

🧠 Topic: Triangle Properties – Right-Angled Check & Area
📥 Input: Three sides of a triangle (entered by the user)
📤 Output:

• Whether the triangle is a right-angled triangle or not
• The area of the triangle

📅 Day 8: Benjamin Bulb Problem

🧠 Topic: Mathematical Patterns – Perfect Squares
📥 Input: Total number of bulbs (entered by the user)
📤 Output: List of bulbs that will remain ON

📅 Day 9: Star Patterns – Pattern 1 & Pattern 2

🧠 Topic: Star Pattern Printing using Nested Loops
📥 Input: Number of rows (entered by the user)
📤 Output: Two different star patterns displayed using loops

⭐ Pattern 1: Left-Aligned Right-Angled Triangle

⭐ Pattern 2: Right-Aligned Right-Angled Triangle

📅 Day 10: Inverted Star Patterns – Pattern 1 & Pattern 2

🧠 Topic: Inverted Triangle Star Patterns
📥 Input: Number of rows (entered by the user)
📤 Output: Two different inverted triangle patterns made using *

⭐ Pattern 1: Right-Aligned Inverted Triangle

⭐ Pattern 2: Left-Aligned Inverted Triangle

📅 Day 11: Centered Pyramid Patterns – Pattern 1 & Pattern 2

🧠 Topic: Symmetric Pyramid Pattern Printing
📥 Input: Number of rows (entered by the user)
📤 Output: Upright and inverted centered pyramid star patterns

⭐ Pattern 1: Centered Pyramid

⭐ Pattern 2: Inverted Centered Pyramid

📅 Day 12: Diamond Star Pattern (Symmetric Hourglass)

🧠 Topic: Complex Star Pattern – Full Symmetric Diamond
📥 Input: Number of rows (typically half the height; entered by the user)
📤 Output: A diamond-shaped star pattern (pyramid + inverted pyramid)

📅 Day 13: Butterfly Star Pattern

🧠 Topic: Symmetric Pattern – Butterfly Shape
📥 Input: Number of rows (entered by the user)
📤 Output: A butterfly-shaped star pattern using * and spaces

📅 Day 14: Right-Diagonal Star Pattern

🧠 Topic: Diagonal Pattern Printing
📥 Input: Number of rows (entered by the user)
📤 Output: A right-slanted diagonal line made using *

⭐ Pattern: Right-Diagonal Line

📅 Day 15: Left-Diagonal Star Pattern

🧠 Topic: Reverse Diagonal Pattern Printing
📥 Input: Number of rows (entered by the user)
📤 Output: A left-slanted diagonal line made using *

⭐ Pattern: Left-Diagonal Line

📅 Day 16: Factorial of a Number using Function

🧠 Topic: Functions & Recursion/Iteration
📥 Input: A positive integer (entered by the user)
📤 Output: Factorial of the given number

📅 Day 17: Frequency of a Digit in a Number using Function

🧠 Topic: Digit Frequency Analysis with Functions
📥 Input:

• A number (e.g., 7555325)
• A digit whose frequency needs to be found (e.g., 5)
  📤 Output: Count how many times the digit appears in the number

📅 Day 18: Convert Decimal to Any Base (2 to 36)

🧠 Topic: Number System Conversion
📥 Input:

• A decimal number (e.g., 255)
• A target base (between 2 and 36)

📤 Output: Equivalent number in the target base

📅 Day 19: Span of an Array

🧠 Topic: Array Analysis – Finding Span
📥 Input: An array of integers (entered by the user or predefined)
📤 Output: The span of the array

📅 Day 20: Search an Element in an Array

🧠 Topic: Array Traversal & Linear Search
📥 Input:

• An array of integers
• A target element to search for
  📤 Output: Index of the element if found; otherwise, a message saying "Not Found"

📅 Day 21: Sum of Two Arrays (Digit-wise Addition)

🧠 Topic: Array Manipulation – Adding Two Numbers Represented as Arrays
📥 Input:

• Two integer arrays, each representing a number (e.g., [9, 8, 7] → 987)
  📤 Output: Resultant array representing the sum of the two numbers

📅 Day 22: Difference of Two Arrays (Supports Negative Result)

🧠 Topic: Subtracting Numbers Represented as Arrays
📥 Input:

• Two arrays of digits: array1 and array2
  (Each represents a number: e.g., [1, 2, 3] → 123)
  📤 Output: A new array representing the difference: array1 - array2
• Output includes a negative sign if array1 < array2

📅 Day 23: Duplicate Brackets Problem

🧠 Topic: Stack – Expression Validation
📥 Input: A string expression containing brackets (e.g., (a + (b) + ((c + d))))
📤 Output: true if duplicate brackets exist, otherwise false

📅 Day 24: Balanced Brackets Problem

🧠 Topic: Stack – Expression Validation
📥 Input: A string expression containing brackets (e.g., (a + [b] + {c}))
📤 Output: true if brackets are balanced and properly nested, otherwise false

📅 Day 25: Next Greater Element Problem

🧠 Topic: Stack – Array Processing
📥 Input: An array of integers
📤 Output: For each element, print the next greater element to its right
(If no such element exists, output -1)

📅 Day 26: Find the Second Greatest Number in an Array

🧠 Topic: Array Traversal & Conditional Logic
📥 Input: An array of integers (unsorted, user input)
📤 Output: The second greatest (second largest) number in the array

📅 Day 28: Largest Area in Histogram

🧠 Topic: Stack – Monotonic Stack Pattern
📥 Input: An array representing the heights of bars in a histogram
📤 Output: The maximum area of the rectangle that can be formed in the histogram

📅 Day 27: Stock Span Problem

🧠 Topic: Stack – Array Processing
📥 Input: An array representing stock prices over n days
📤 Output: An array where each element represents the stock span on that day

📅 Day 29: Sliding Window Maximum

🧠 Topic: Deque (Double-Ended Queue) / Sliding Window Technique
📥 Input: An array of integers and a window size k
📤 Output: An array of maximum values for each sliding window of size k

📅 Day 30: Infix Expression Evaluation

🧠 Topic: Stack | Expression Parsing
📥 Input: A string containing a valid infix expression (e.g., "2 + 3 * (4 - 1)")
📤 Output: The evaluated integer result of the expression

📅 Day 31: Postfix Expression Evaluation

🧠 Topic: Stack | Expression Evaluation
📥 Input: A postfix expression string (e.g., "231*+9-")
📤 Output: Evaluated integer result