One of the most frequent hurdles learners face is the subarray with given sum problem. At first glance. If the array contains negative numbers, the standard “sliding window” or “two-pointer” technique fails. Why? This is because adding an element could potentially decrease the total sum, while removing one could potentially increase it. To solve this …
Subarray with Given Sum – Handles Negative Numbers Read More »
When you first start learning about data storage, arrays are usually the go-to. But inserting one person at the front requires moving every single item in an array, which is exhausting for a computer. This is the exact problem DSA linked lists were built to solve. Instead of needing a single, giant block of memory, …
When you first learn about sorting, you probably start with algorithms that compare numbers, such as “Is 5 greater than 3?” While intuitive, these comparison-based methods have a mathematical speed limit. If you are dealing with massive datasets of integers or strings, you need a different strategy. This is where DSA radix sort comes into …
Bubble sort works like arranging cards by swapping neighbouring ones repeatedly. Larger values rise into place quickly, but smaller values near the end move forward slowly, one step at a time, making the method inefficient for larger datasets in DSA. The cocktail sort algorithm was designed specifically to solve this issue. Often referred to as …
When you start learning about data structures, the linked list often feels confusing. You can’t simply jump to an index, unlike arrays. If someone asks you to find the middle of linked list elements or, more specifically, to delete middle of the linked list nodes, you might initially feel stuck. Let’s look at how to …
Learning Data Structures and Algorithms (DSA) often feels like solving a complex puzzle. One moment you are comfortable with a min heap, where the smallest element sits at the top, and the next, a problem requires you to flip that logic entirely. Understanding how to convert min heap to max heap is a crucial skill …
It may appear straightforward to find the largest number with a specific amount of digits and a certain sum of those digits, but you need to be “greedy” to make sure the value is really the biggest it can be. This problem comes up a lot in class when people talk about how to get …
Find the Largest Number with Given Number of Digits and Sum of Digits Read More »
To find the smallest number with a certain number of digits (D) and a certain sum (S), we need to put the digits from 0 to 9 in a way that they add up to S while keeping the overall value as low as feasible. Students generally have trouble with this problem because they have …
First non repeating character in a string that doesn’t repeat is a popular problem for pupils. It sounds easy to find the “K’th” instance of such a character, but it gets harder when you have to do it. Many learners struggle to balance memory usage and speed when working with large datasets. It’s quite important …
Finding the right “window” size is the trickiest part of working with k sorted lists. Each list needs to contribute to the range, and the difference between the smallest and largest integers should be minimal. Many technical interviews feature this question because it assesses your ability to manage multiple pointers and use tools like heaps …
Smallest Range with Elements from k Sorted Lists Read More »
