Key-value pairs for lookup Day 136 of 149 👉 Full deep-dive with code examples The Phone Book Analogy Remember phone books? Find "Smith" → Flip directly to S section Look up the name → Get the phone number You don't scan from the beginning! Maps work like phone books! You look up a "key" (name) and instantly get a "value" (phone number). The Problem They Solve Looking up things in a list is slow: 1 million items? Check one by one? That could take forever! With a map: Store key → value pairs Look up by key Get the answer instantly! How Maps Work Maps store pairs of things: Key → Value "name" → "Alice" "age" → 30 "city" → "Sydney" Enter fullscreen mode Exit fullscreen mode To get a value, just use the key: Ask for "name" → Get "Alice" Ask for "age" → Get 30 No searching through everything! Why They're Fast Behind the scenes, maps use a smart trick: Convert the key to a number (hashing) Use that number to find the exact location Go directly there Like a library catalog card telling you exactly which shelf.…