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This article explains how to determine whether an integer array contains any duplicate values using a PHP solution that iterates the array, stores seen elements in an associative map, and returns true on the first repeat, with O(n) time and space complexity.
This article presents the LeetCode 764 problem of finding the largest axis‑aligned plus sign in a binary grid, explains the preprocessing and simulation approach using four directional prefix arrays, analyzes time and space complexity, and provides complete Java, C++, Python, and TypeScript implementations.
This article introduces the GMP library for high‑precision arithmetic in PHP and explains a fast multiplication algorithm that reduces complexity by splitting large numbers, then provides a complete PHP implementation demonstrating recursive Karatsuba‑style multiplication for big integers.
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This article explains the Aho‑Corasick automaton, a classic multi‑pattern matching algorithm that builds a Trie with fail pointers to achieve linear‑time search over massive keyword sets, and demonstrates a Java implementation for highlighting keywords in HTML documents.
The article first highlights Tencent's Q1 2025 financial results and user metrics, then introduces the LeetCode 2013 'Detect Squares' problem, describing its requirements, example, and offering Java, C++, Python, and array‑based solutions along with time and space complexity analysis.
The article first critiques a hiring manager’s salary‑balance rationale for a 985‑master candidate, then presents LeetCode problem 1546 on finding the maximum number of non‑overlapping subarrays whose sums equal a target, explaining the solution using prefix sums and providing Java and C++ implementations.
The article introduces intelligent supply chain planning algorithms—including network design, inventory layout, and simulation—detailing their optimization models, high‑performance solving techniques, and real‑world impact on cost reduction, efficiency, and service experience across large‑scale logistics operations.
The article presents how operations‑optimization and simulation algorithms empower supply‑chain planning—covering network design, inventory layout, and large‑scale simulation—to achieve cost reduction, efficiency gains, and enhanced user experience through advanced algorithmic solutions.
This article explains how to determine whether an integer array contains any duplicate values by iterating through the elements, using an associative map in PHP to track occurrences, and returning true if a repeat is found or false otherwise, including code examples and analysis of time and space complexity.
The article first discusses how many large companies now filter candidates by strict academic degree requirements, then presents LeetCode problem 407 (Trapping Rain Water II) and provides a detailed Dijkstra‑variant solution using a min‑heap, including full Java and C++ implementations and complexity analysis.
The article reflects on why mid‑career engineers are often relegated to legacy‑maintenance work, argues that such roles can be leveraged for growth by modernizing systems and adopting AI, and then presents the classic Valid Parentheses coding challenge, explaining a stack‑based solution with implementations, complexity analysis, and common pitfalls.
In algorithm‑focused internet company interviews, asking thoughtful reverse‑questions—such as the core competitiveness of algorithm engineers, challenging project problems, debugging experiences, and methods for guaranteeing correctness—demonstrates genuine interest, technical depth, and a passion for improvement, leaving a strong positive impression on interviewers.
This article explains the fundamentals of recursion in Java, covering its definition, advantages and disadvantages, differences from iteration, and provides practical examples such as traversing comment and department trees, along with code snippets, performance considerations, and improvement strategies using depth control and Stream API.
This article introduces LeetCode problem 1448 about counting good nodes in a binary tree, explains the definition of a good node, provides example inputs and outputs, outlines constraints, offers a detailed DFS analysis, and presents complete Java and C++ implementations.
Learn what the Luhn (mod‑10) algorithm is, its real‑world applications such as credit‑card and IMEI validation, step‑by‑step calculation examples, and see practical TypeScript and JavaScript implementations that you can integrate into your web projects.
This article explains the concept of pre-order (root-left-right) tree traversal, demonstrates how to represent binary trees in PHP, provides recursive and stack‑based iterative implementations, and includes an interactive script that lets users build a tree and choose traversal methods, with full example code.
Given an integer array, the task is to find the maximum sum of a non‑empty subarray after optionally deleting at most one element, which can be solved via dynamic programming using two states to track sums with and without a deletion, as demonstrated with Java and C++ implementations.
This article explains the concept of prefix sums, demonstrates how to build and use a prefix‑sum array in PHP with clear code examples, and discusses when the technique is advantageous and its limitations, enabling O(1) interval sum queries after an O(n) preprocessing step.
This article introduces the sliding window technique, demonstrates efficient PHP implementations for computing averages and handling real-time streams, provides optimization strategies, and outlines practical applications such as financial analysis, network monitoring, and recommendation systems, highlighting performance considerations for backend development.