Meta Hard Interview Questions

Instagram relies on providing quick access to user feeds, which requires an efficient cache management system. Design an LRU Cache to ensure optimal performance.Class LRUCache:
- LRUCache(int capacity): Initializes the cache with a positive size capacity.
- int get(int key): Returns the value of the key if the key exists, otherwise returns -1.
- void put(int key, int value): Update the value of the key if present, or add the key-value pair if not existing. When the cache reaches its capacity, it should invalidate the least recently used item before inserting a new item.Example 1:
Input: LRUCache(2); cache.put(1, 1); cache.put(2, 2); cache.get(1); cache.put(3, 3); cache.get(2); cache.put(4, 4); cache.get(1); cache.get(3); cache.get(4);
Output: 1; -1; 3; 4Constraints:
- capacity is always positive and will not exceed 1000
- The operations get and put will always be called with valid keys.

This problem simulates navigation through Facebook Events. Efficient pathfinding is crucial for enhancing user experience in discovering events.
Given an undirected graph represented as an adjacency list, return the shortest path from node start to node end.Example 1:
Input: edges = [[0, 1], [1, 2], [2, 3]], start = 0, end = 3
Output: [0, 1, 2, 3]
Explanation: The shortest path from node 0 to node 3 is 0 -> 1 -> 2 -> 3.Example 2:
Input: edges = [[0, 1], [1, 2], [0, 2], [2, 3]], start = 0, end = 3
Output: [0, 2, 3]Constraints:
- 1 <= edges.length <= 10^4
- Each edge is a pair of distinct integers.

This problem is important for optimizing the chat list experience in the Messenger app. By ensuring quick access to frequently used contacts, we can enhance user engagement.
Given a string s, find the length of the longest substring containing at most two distinct characters.Example 1:
Input: s = "eceba"
Output: 3
Explanation: The substring is "ece" which its length is 3.Example 2:
Input: s = "ccaabbb"
Output: 5
Explanation: The substring is "aabbb" which its length is 5.Constraints:
- 1 <= s.length <= 10^5
- s consists of English letters, digits, symbols, and spaces.