Introduction

In this blog post, we'll share the most commonly asked coding interview questions at ZipRecruiter. If you don't have months to study for your interviews, you can use AI tools like Chatmagic to generate solutions quickly and efficiently - helping you pass the interviews and get the job offer!

Problem #1: Find the Length of the Longest Common Prefix

You are given two arrays with positive integers arr1 and arr2. A prefix of a positive integer is an integer formed by one or more of its digits, starting from its leftmost digit. For example, 123 is a prefix of the integer 12345, while 234 is not. A common prefix of two integers a and b is an integer c, such that c is a prefix of both a and b. For example, 5655359 and 56554 have common prefixes 565 and 5655 while 1223 and 43456 do not have a common prefix. You need to find the length of the longest common prefix between all pairs of integers (x, y) such that x belongs to arr1 and y belongs to arr2. Return the length of the longest common prefix among all pairs. If no common prefix exists among them, return 0. Example 1: Input: arr1 = [1,10,100], arr2 = [1000] Output: 3 Explanation: There are 3 pairs (arr1[i], arr2[j]): - The longest common prefix of (1, 1000) is 1. - The longest common prefix of (10, 1000) is 10. - The longest common prefix of (100, 1000) is 100. The longest common prefix is 100 with a length of 3. Example 2: Input: arr1 = [1,2,3], arr2 = [4,4,4] Output: 0 Explanation: There exists no common prefix for any pair (arr1[i], arr2[j]), hence we return 0. Note that common prefixes between elements of the same array do not count. Constraints: 1 <= arr1.length, arr2.length <= 5 * 104 1 <= arr1[i], arr2[i] <= 108

Topics: Array, Hash Table, String, Trie

Problem #2: Rotting Oranges

You are given an m x n grid where each cell can have one of three values: 0 representing an empty cell, 1 representing a fresh orange, or 2 representing a rotten orange. Every minute, any fresh orange that is 4-directionally adjacent to a rotten orange becomes rotten. Return the minimum number of minutes that must elapse until no cell has a fresh orange. If this is impossible, return -1. Example 1: Input: grid = [[2,1,1],[1,1,0],[0,1,1]] Output: 4 Example 2: Input: grid = [[2,1,1],[0,1,1],[1,0,1]] Output: -1 Explanation: The orange in the bottom left corner (row 2, column 0) is never rotten, because rotting only happens 4-directionally. Example 3: Input: grid = [[0,2]] Output: 0 Explanation: Since there are already no fresh oranges at minute 0, the answer is just 0. Constraints: m == grid.length n == grid[i].length 1 <= m, n <= 10 grid[i][j] is 0, 1, or 2.

Topics: Array, Breadth-First Search, Matrix