You do not need to check every buy-sell pair. One pass, two variables, and the right greedy instinct is all it takes. Here is the full breakdown of LeetCode 121 with a deep dry run and interview tips.
Rahul Kumar
What if you could find the majority element without counting anything? The Boyer-Moore Voting Algorithm does exactly that, in O(n) time and O(1) space. Here is the full breakdown.
Rahul Kumar
Squaring a sorted array breaks its order. Learn how the two pointer technique rebuilds sorted squares in a single O(n) pass, with a full dry run, common mistakes, and interview tips.
Rahul Kumar
On Day 5 of the 250 Days DSA Challenge, we crack LeetCode 75 Sort Colors using the Dutch National Flag algorithm. One pass. Three pointers. Zero extra space. Here is exactly how it works and why every pointer decision matters.
Rahul Kumar
Day 4 of the 250 Days DSA Challenge. LeetCode 11 Container With Most Water is a visual problem hiding a clean logical constraint. This post breaks down the full approach with a detailed dry run, pointer movement reasoning, and interview ready insights.
Rahul Kumar
Day 3 of the 250 Days DSA Challenge. LeetCode 15 Three Sum looks intimidating at first, but once you sort the array and fix one element, it reduces to the exact same Two Sum II problem we solved yesterday. This post breaks down the full approach with a detailed dry run.
Rahul Kumar
Day 2 of the 250 Days DSA Challenge. LeetCode 167 Two Sum II looks like a simple sum problem, but the sorted array changes everything. This post breaks down the Two Pointers technique with a detailed dry run. Perfect for anyone learning how to think with pointers.
Rahul Kumar
Kicking off a 250-day DSA challenge with LeetCode 283 Move Zeroes. This post breaks down the Fast–Slow Two Pointer technique with a detailed dry run, visual step-by-step walkthrough, and interview-ready insights. Perfect for beginners and anyone revisiting array fundamentals.
Rahul Kumar