Meta E5 | SWE Product | Full loop

Given a string s of '(', ')', and lowercase English characters. Your task is to remove the minimum number of parentheses so that the resulting parentheses string is valid. Return any valid string.

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree.

Calculate the weighted sum of integers in a nested list structure. The specific variation was not detailed, but generally involves defining weights based on depth or reverse depth for each integer in the nested array.

Given a 2D grid where each cell can be one of three values: 0 (empty land), 1 (building), or 2 (obstacle). A variation of finding the shortest total distance from an empty land cell to all buildings. The candidate mentioned a multisource BFS approach, hinting at the standard solution pattern.

Design a system for a live contest leaderboard similar to HackerRank, accommodating various custom functional requirements that were not explicitly stated.