Memoization
Domain: Algorithms
🎯 Motivation
A top-down DP technique: store results of expensive function calls and return the cached result when the same inputs occur again.
📋 Concrete Example
Fibonacci with memo: cache = {}; def fib(n): if n in cache: return cache[n]; ... cache[n] = result; return result. First call computes, later calls are instant.
🔗 Analogy
A student who writes down the answer to a maths problem in a notebook. When asked the same problem again, they just look it up instead of recalculating.