#146 Medium
LRU Cache
Design a fixed-capacity cache that evicts the least-recently-used entry when full. Both `get` and `put` must run in O(1), which forces the combination of a hash map (for direct lookup) with a doubly-linked list (for ordering).
Hash TableLinked ListDesignDoubly-Linked List
2 approaches
#153 Medium
Find Minimum in Rotated Sorted Array
Given a sorted array that has been rotated, find the minimum element efficiently. The key insight is recognizing a structural property that lets us eliminate half the search space at each step.
ArrayBinary Search
2 approaches
#215 Medium
Kth Largest Element in an Array
Given an array of integers and a position `k`, find the element that would rank `k`th if sorted in descending order. The key insight is recognizing that you don't need to sort the entire array—you only need to maintain the top `k` candidates efficiently.
ArrayDivide and ConquerSortingHeap (Priority Queue)Quickselect
2 approaches