leetcode_practice problem solved record (google sheet) https://docs.google.com/spreadsheets/d/1-b54Jo-Rnp6ffB01H-FomZiE4ELqj-53FRunePL2nEU/edit?usp=sharing C++ Review note https://hackmd.io/@f4Kxc3aUTnKYuz7Y-4CUPQ/H1a9Pj2TU