Category: Algorithm

  • Efficiently Calculating Tree Heights After Subtree Removal in PHP

    Intuition The problem involves calculating the height of a binary tree after removing subtrees rooted at specific nodes. To efficiently handle multiple queries, we can preprocess the tree to store information about node depths and levels. By leveraging this information, we can quickly determine the new height of the tree after each removal. Approach Complexity…

  • Removing Sub-Folders from a List of Folders in PHP

    Intuition The problem requires removing subfolders from a list of folder paths. The simplest way to identify subfolders is to check if one path starts with another parent path. By sorting the folders lexicographically, subfolders will always appear immediately after their corresponding parent folders, which makes it easy to filter them out with a single…

  • Palindrome Number: A PHP Solution

    Intuition The initial thought to solve this problem is to convert the integer into a string. This allows us to leverage string manipulation functions to easily reverse the string and compare it to the original. By comparing the original and reversed strings, we can determine if the number is a palindrome. Approach Complexity Problem Given…

  • A Comprehensive Guide to the Two Sum Problem in PHP

    Intuition When first encountering the Two Sum problem, a straightforward approach might involve nested loops. For each element in the array, we could iterate through the remaining elements, checking if their sum equals the target. However, this approach would result in a time complexity of O(n^2). Approach To improve upon the brute-force approach, we can…