Here are some questions from an on-site technical interview at Facebook in 2019. You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the previous version, all the versions after a bad version are also bad. Suppose you have [1, 2, ..., n] and you want to find out the first bad one, which causes all the following ones to be bad. You are given an APIbool isBadVersion(version) which will return whetherversion is bad. Implement a function to find the first bad version. You should minimize the number of calls to the API. Given n = 5, and version = 4 is the first bad version.call isBadVersion(3) -> falsecall isBadVersion(5) -> truecall isBadVersion(4) -> trueThen 4 is the first bad version. Design a data structure that supports the following two operations:search(word) can search a literal word or a regular expression string containing only letters. means it can represent any one letter. search("pad") -> falsesearch("bad") -> truesearch(".ad") -> truesearch("b..") -> true You may assume that all words are consist of lowercase lettersGiven a 2d grid map of'1's (land) and'0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water. Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results. Note: The input string may contain letters other than the parenthesesOutput: ["()()()", "(())()"]Output: ["(a)()()", "(a())()"]Good luck! Note: These were quite difficult and seems like even more difficult in person.