Count the Digits That Divide a Number | LeetCode 2520 | C++ Solution with Explanation

In this video, we solve LeetCode Problem 2520: Count the Digits That Divide a Number using a simple and intuitive approach that is perfect for beginners.

We begin by understanding the problem statement and what it means for a digit to divide a number. Then, we walk through step-by-step examples to clearly see how each digit of the number is processed and checked.

The key idea is to extract each digit from the given number and check whether it divides the original number completely. Using basic math operations like modulus and division, we can efficiently solve this problem without using any extra space.

In this video, you will learn how to approach the LeetCode 2520 solution, understand count digits that divide a number, and apply digit extraction techniques for solving LeetCode easy problems. This problem is very useful for beginners learning math-based DSA problems and preparing for coding interviews using C++ solutions.

🧠 What You Will Learn in This Video:
How to extract digits from a number
Using modulus and division operations
Step-by-step dry run with examples
Checking divisibility conditions
Clean and beginner-friendly C++ implementation
Time and Space Complexity analysis
🧩 Problem Summary:

You are given an integer num.

Your task is to count how many digits in num:

Are non-zero
Divide the number completely (i.e., num % digit == 0)

Return the total count of such digits.

💡 Approach Explained:

We follow a simple process:

Store the original number
Extract digits one by one using % 10
For each digit:
Check if it is not zero
Check if it divides the original number
Increment the count if both conditions are satisfied

Repeat until all digits are processed.

⏱️ Complexity Analysis:
Time Complexity: O(d)**
Where d is the number of digits in the number
Space Complexity: O(1)
💻 Topics Covered:
Mathematics
Digit Manipulation
Modulus operation
Basic DSA concepts
🚀 Why Watch This Video?

This problem is a great example of how basic math and logic can be used to solve problems efficiently. It helps you build strong fundamentals in number manipulation, which is important for many coding interview questions.

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Видео Count the Digits That Divide a Number | LeetCode 2520 | C++ Solution with Explanation канала PATEL MANN