Robina Li

Welcome to My Technical Blog

Exploring algorithms, data structures, and software engineering insights through LeetCode solutions in Python.
NOTE: This blog is still under construction and some python code blocks may not be rendered correctly when converted from C++ with AI.

169+ Problems Solved

3 Difficulty Levels

20+ Categories

Latest Posts

Mar 21, 2026

713. Subarray Product Less Than K

leetcodemediumarraysliding-window

Mar 20, 2026

309. Best Time to Buy and Sell Stock with Cooldown

leetcodemediumdpstock

Mar 19, 2026

362. Design Hit Counter

leetcodemediumdesignqueuesliding-window

Mar 18, 2026

1448. Count Good Nodes in Binary Tree

leetcodemediumtreedfsbfs

Mar 17, 2026

1376. Time Needed to Inform All Employees

leetcodemediumtreegraphdfsbfs

Mar 16, 2026

2406. Divide Intervals Into Minimum Number of Groups

leetcodemediumintervalheapsweep-line

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All Posts

Jan 25, 2026

213. House Robber II

leetcodemediumarraydynamic-programming

Jan 24, 2026

622. Design Circular Queue

leetcodemediumarraylinked-listdesignqueue

Jan 23, 2026

1233. Remove Sub-Folders from the Filesystem

leetcodemediumarraystringtriesorting

Jan 22, 2026

1801. Number of Orders in the Backlog

leetcodemediumarrayheappriority-queuesimulation

Jan 21, 2026

63. Unique Paths II

leetcodemediumarraydynamic-programmingmatrix

Jan 20, 2026

498. Diagonal Traverse

leetcodemediumarraymatrixsimulation

Jan 20, 2026

189. Rotate Array

leetcodemediumarray

Jan 20, 2026

Algorithm Templates: Search

Minimal, copy-paste C++ for binary search, rotated arrays, 2D search, and answer-space search. Matches Data Structures lower/upper bound style.

leetcodetemplatessearchbinary-search

Jan 20, 2026

327. Count of Range Sum

leetcodehardarraydivide-and-conquer

Jan 19, 2026

236. Lowest Common Ancestor of a Binary Tree

leetcodemediumtreedfs