Today I worked on the Valid Parentheses problem, a classic problem that tests stack-based problem-solving and logical thinking. The goal is simple: determine whether a string containing (), {}, and [] is valid. A string is valid when every opening bracket has the correct closing bracket, and the brackets are properly nested. I solved this using a Stack in JavaScript. Whenever an opening bracket a…
Today’s challenge was to find the longest common prefix shared by all strings in an array. I implemented the solution in JavaScript and successfully passed all 126 test cases. The approach is straightforward and easy to understand. I started with the first string as the reference and compared each of its characters with the corresponding character in every other string. If a character does not ma…
The problem looks simple at first, but it is a great example of how choosing the right data structure can make a solution both clean and efficient. The goal is to determine whether a string containing (), {}, and [] is valid. Every opening bracket must have the correct closing bracket, and brackets must close in the proper order. I solved it using a Stack. The approach is straightforward: Create …
Today’s challenge was LeetCode – Zigzag Conversion, a great problem for practicing string manipulation, arrays, loops, and direction-based traversal in JavaScript. The problem gives us a string and a number of rows. We need to arrange the characters in a zigzag pattern and then read the characters row by row to generate the final string. For example: PAYPALISHIRING With numRows = 3, the character…
The goal is simple but interesting: given a string s, find the longest substring that reads the same forward and backward. For example: Input: "babad" Output: "bab" or "aba" 💡 Approach: Expand Around Center Instead of generating every possible substring and checking whether it is a palindrome, I used the Expand Around Center technique. Every palindrome has a center: Odd-length palindrome → one ch…
