Introduction

In this blog post, we'll share the most commonly asked coding interview questions at Nextdoor. 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: Compare Version Numbers

Given two version strings, version1 and version2, compare them. A version string consists of revisions separated by dots '.'. The value of the revision is its integer conversion ignoring leading zeros. To compare version strings, compare their revision values in left-to-right order. If one of the version strings has fewer revisions, treat the missing revision values as 0. Return the following: If version1 < version2, return -1. If version1 > version2, return 1. Otherwise, return 0. Example 1: Input: version1 = "1.2", version2 = "1.10" Output: -1 Explanation: version1's second revision is "2" and version2's second revision is "10": 2 < 10, so version1 < version2. Example 2: Input: version1 = "1.01", version2 = "1.001" Output: 0 Explanation: Ignoring leading zeroes, both "01" and "001" represent the same integer "1". Example 3: Input: version1 = "1.0", version2 = "1.0.0.0" Output: 0 Explanation: version1 has less revisions, which means every missing revision are treated as "0". Constraints: 1 <= version1.length, version2.length <= 500 version1 and version2 only contain digits and '.'. version1 and version2 are valid version numbers. All the given revisions in version1 and version2 can be stored in a 32-bit integer.

Topics: Two Pointers, String

Problem #2: Merge Intervals

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input. Example 1: Input: intervals = [[1,3],[2,6],[8,10],[15,18]] Output: [[1,6],[8,10],[15,18]] Explanation: Since intervals [1,3] and [2,6] overlap, merge them into [1,6]. Example 2: Input: intervals = [[1,4],[4,5]] Output: [[1,5]] Explanation: Intervals [1,4] and [4,5] are considered overlapping. Constraints: 1 <= intervals.length <= 104 intervals[i].length == 2 0 <= starti <= endi <= 104

Topics: Array, Sorting