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 22, 2026

134. Gas Station

134. Gas Station

leetcodemediumgreedyarray

Mar 21, 2026

713. Subarray Product Less Than K

713. Subarray Product Less Than K

leetcodemediumarraysliding-window

Mar 20, 2026

309. Best Time to Buy and Sell Stock with Cooldown

309. Best Time to Buy and Sell Stock with Cooldown

leetcodemediumdpstock

Mar 19, 2026

362. Design Hit Counter

362. Design Hit Counter

leetcodemediumdesignqueuesliding-window

Mar 18, 2026

1448. Count Good Nodes in Binary Tree

1448. Count Good Nodes in Binary Tree

leetcodemediumtreedfsbfs

Mar 17, 2026

1376. Time Needed to Inform All Employees

1376. Time Needed to Inform All Employees

leetcodemediumtreegraphdfsbfs

View All Posts

All Posts

Nov 24, 2025

[Medium] 277. Find the Celebrity

[Medium] 277. Find the Celebrity

leetcodealgorithmmediumcppgraphtwo-pointersproblem-solving

Nov 24, 2025

[Medium] 1762. Buildings With an Ocean View

[Medium] 1762. Buildings With an Ocean View

leetcodealgorithmmediumcpparraystackmonotonic-stackproblem-solving

Nov 24, 2025

[Medium] 129. Sum Root to Leaf Numbers

[Medium] 129. Sum Root to Leaf Numbers

leetcodealgorithmmediumcpptreedfsproblem-solving

Nov 24, 2025

[Medium] 1209. Remove All Adjacent Duplicates in String II

[Medium] 1209. Remove All Adjacent Duplicates in String II

leetcodealgorithmmediumcppstringstacktwo-pointersproblem-solving

Nov 24, 2025

[Hard] 489. Robot Room Cleaner

[Hard] 489. Robot Room Cleaner

leetcodealgorithmhardcppdfsbacktrackingproblem-solving

Nov 24, 2025

[Hard] 32. Longest Valid Parentheses

[Hard] 32. Longest Valid Parentheses

leetcodealgorithmhardcppstringdynamic-programmingstackproblem-solving

Nov 24, 2025

[Easy] 938. Range Sum of BST

[Easy] 938. Range Sum of BST

leetcodealgorithmeasycpptreebstdfsproblem-solving

Nov 24, 2025

[Easy] 408. Valid Word Abbreviation

[Easy] 408. Valid Word Abbreviation

leetcodealgorithmeasycppstringtwo-pointersproblem-solving

Nov 24, 2025

[Easy] 1047. Remove All Adjacent Duplicates In String

[Easy] 1047. Remove All Adjacent Duplicates In String

leetcodealgorithmeasycppstringstacktwo-pointersproblem-solving

Nov 24, 2025

Algorithm Templates: String Processing

Minimal, copy-paste C++ for sliding window, two pointers, string matching, manipulation, and parsing. See also Arrays & Strings for KMP and rolling hash.

leetcodetemplatesstring