📄️ 🟩 Best Time to Buy and Sell Stock (#121)121)📄️ 🟩 Contains Duplicate II (#219)219)📄️ 🟨 Longest Substring Without Repeating Characters (#3)3)📄️ 🟨 Longest Repeating Character Replacement (#424)424)📄️ 🟥 Minimum Window Substring (#76)76)