Implement a recency cache and min-coins DP

The algorithm round covered two coding problems: 1. Design a fixed-capacity in-memory key-value cache that evicts the least recently accessed item when full. Implement: - `Cache(int capacity)` - `int get(int key)` which returns `-1` if the key does not exist - `void put(int key, int value)` Both operations should run in O(1) average time. 2. Given a list of positive coin denominations and a target amount, return the minimum number of coins needed to form exactly that amount. If the amount cannot be formed, return `-1`. You may use each denomination any number of times.