LeetCode Algorithms & Engineering Notes

A structured repository containing algorithmic problem breakdowns, fundamental data structure patterns, and practical firmware/BSP engineering logs.

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Repository Index

1. Data Structures & Algorithms

Topic	Note File	Key Concepts & Patterns
Monotonic Stack	monotonic stack.md	Next Greater Element, Histogram Area, Range Minimums, O(N) Traversal
Trees & Graphs	Binary Tree,Hash table, dfs.md	Tree Traversals, Lowest Common Ancestor, DFS Recursion, Subtree Evaluation
Dynamic Programming	DP, matrix.md dynamic_programming(1).md dynamic_programming(2).md	State Transitions, 1D/2D Memoization, Matrix Paths, Subsequence Optimization
Binary Search	binary_search(1).md	Boundary Condition Handling, Search Space Reduction, Rotated Arrays
Advanced Structures	segment tree.md	Range Query and Update, Tree Decomposition

2. Embedded & System Engineering Logs

Category	Note File	Focus Areas
BSP & Tooling	working_diary.md	MediaTek SP Flash Tool configuration, Android ADB debugging, terminal workflows

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Algorithmic Solution Framework

Each algorithmic problem entry is structured around a reproducible problem-solving methodology:

1. Problem Statement & Constraints:
   • Extraction of input/output requirements, edge cases, and constraint bounds.
2. Visual & Intuitive Analysis:
   • Diagrammatic representation of pointers, tree structures, or stack states.
3. Complexity Guarantees:
   • Optimal time complexity (e.g., reducing $O(N^2)$ to $O(N)$ using Monotonic Stacks).
   • Space complexity evaluation for recursion stacks and auxiliary memory.
4. Implementation & Refactoring:
   • Clean, idiomatic source code with considerations for boundary checks.

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Highlighted Problem Categories

Monotonic Stack Pattern

Focuses on problems requiring linear-time solutions for finding the nearest larger or smaller element. Key examples include calculating the largest rectangular area under a histogram and processing stock spans.

Dynamic Programming & Matrix Traversal

Covers optimal substructure identification, recurrence relations, and memory optimization (space reduction from 2D arrays to 1D sliding windows).

Binary Trees and DFS

Explores tree structure manipulation, depth evaluation, path tracing, and recursive partitioning strategies.

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Embedded Engineering Logs

The working_diary.md tracks hands-on firmware and system bring-up notes, including:

• MediaTek (MTK) Flashing Workflow:
  • Image flashing procedures using SP_Flash_Tool_Selector.
  • Execution permission setup and file system access handling on Linux environments.
• Android User-Build Debugging:
  • Enabling developer mode and USB/wireless debugging on target devices.
  • Device verification and shell access via adb devices and adb shell.

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Usage

Browse the corresponding Markdown files directly on GitHub or clone the repository locally for reference:

git clone https://github.com/Kylechen0815/leetcode_note.git
cd leetcode_note