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 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