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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 presents the LeetCode 1514 'Maximum Probability Path' problem, explains the algorithm using a priority‑queue approach, provides full Java and C++ implementations, and concludes with a promotional book giveaway encouraging readers to follow the public account.
This article presents LeetCode problem 1514, which asks for the path with the highest success probability in an undirected weighted graph, explains the problem statement, constraints, and provides detailed Java and C++ implementations using a priority‑queue based Dijkstra‑like algorithm.
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.
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.
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.
The Word Break problem (LeetCode 139) asks whether a given string can be segmented into a sequence of dictionary words, and can be solved efficiently with dynamic programming by tracking reachable prefixes in a boolean array, as demonstrated by concise Java and C++ implementations.
The Next Permutation problem asks to rearrange an integer array into the immediate lexicographically larger ordering—or the smallest order if none exists—by scanning from the right to find the first decreasing pair, swapping with the next larger element, and reversing the suffix, using O(1) extra space, with implementations provided in Java, C++, and Python.
LeetCode 57 asks you to insert a new interval into a sorted list of non‑overlapping intervals, merging any overlaps so the result stays sorted and disjoint, and the article explains the O(n) algorithm and provides concise implementations in Java, C++ and Python.
This article explains the LeetCode 31 "Next Permutation" problem, provides a detailed analysis of the algorithmic approach, and presents complete in‑place solutions in Java, C++, and Python, along with constraints and example cases.
The article first shares a personal anecdote about job background checks and then presents a detailed explanation of LeetCode problem 5 – Longest Palindromic Substring – including problem description, dynamic‑programming analysis, recurrence formula, and complete Java and C++ code examples.
The article explains LeetCode 491, requiring all non‑decreasing subsequences of length ≥2 from an integer array, and details a depth‑first search approach that uses a per‑level set to skip duplicates, with complete example implementations in Java, C++, C, and Python.
The article explains LeetCode 814, where a binary tree of 0s and 1s is pruned by recursively removing subtrees lacking a 1, using a post‑order traversal that returns null for nodes with value 0 and no retained children, achieving O(n) time and O(h) space.
LeetCode 34 asks for the first and last indices of a target in a non‑decreasing integer array, returning [-1,-1] when absent, and can be solved in O(log n) time by applying two binary‑search passes—one locating the leftmost occurrence and the other the rightmost—illustrated with Java, C++, and Python implementations.
The article argues that a backend engineer’s growth hinges on mastering communication, clean coding, and architecture design by consistently abstracting problems—illustrated through Go’s ServerCodec and I/O interfaces, efficient algorithms like Trie‑based word search, and Rust’s ownership model—while recommending early Go/Rust study, reading well‑commented libraries, and hands‑on service building.
The article first shares a frustrated JD interview experience regarding a 'personality' assessment, then introduces LeetCode problem 814 – Binary Tree Pruning – detailing the problem statement, examples, and providing concise post‑order traversal solutions in Java, C++, and Python.
The article shares a candid interview anecdote about reasons for leaving a job, then presents LeetCode problem 542 “01 Matrix”, explains its DP and BFS approaches, and provides full Java, C++, and Python implementations.
This article presents LeetCode problem 112 "Path Sum", detailing the problem statement, example inputs and outputs, constraints, a recursive analysis, and complete reference implementations in Java, C++, and Python for determining whether a root‑to‑leaf path equals a given target sum.
The Zigzag Conversion algorithm rearranges an input string into a Z‑shaped pattern across a specified number of rows, tracks the current row while toggling direction at the top and bottom, stores characters per row, and finally concatenates the rows to produce the transformed string, with reference implementations in C++, Java, and Python.