femakin/Kepler

Kepler Test

Welcome! Take a look at the instructions below to get started.

Instructions

In this assessment, there are 3 issues to tackle, one of them is UI-related, and each should typically take 15 minutes (each) to solve. Feel free to ask questions and communicate about how you're thinking about the problem as you proceed.

Start off by creating a new local branch for your work. You should use your full name as the branch name, e.g., john-doe. Once you're done, please commit your changes and push the branch.

Good luck!

Installation

After cloning repository, install dependencies:

npm install

Problems

Here, we have some code files with incomplete snippets along with corresponding tests. Your task is to update the existing code to ensure the successful execution of the tests. The provided code snippets are intended as a starting point, but you have the flexibility to modify or entirely replace them based on your approach.

Problem 1 - Group by

File	Test
src/problem1-lis.ts	src__tests__/problem1-lis.ts

In src/problem1-groupby.ts we have a function groupBy that takes in an array of objects arr and a key. attempts to groups the objects by a key

Example 1:

Input:

 key = 'day'
 arr = [
   { day: 'Mon', time: '13:00' }
   { day: 'Mon', time: '14:00' }
   { day: 'Tue', time: '09:00' }
   { day: 'Tue', time: '11:00' }
 ]

Output:

 output = {
    'Mon':  [
      { day: 'Mon', time: '13:00' }
      { day: 'Mon', time: '14:00' }
    ],
    'Tue': [
      { day: 'Tue', time: '09:00' }
      { day: 'Tue', time: '11:00' }
    ]
 }

Problem 2 - Longest Increasing Subsequence

File	Test
src/problem1-lis.ts	src__tests__/problem1-lis.ts

In src/problem1-lis.ts, we have a function getLongestIncreasingSubsequence, It should take in an array of integers as input and return the length of the longest increasing subsequence. A subsequence is a sequence of numbers in an array that are in the same order as they appear in the array, but not necessarily contiguous. The numbers in the subsequence must be strictly increasing.

Example 1:

Input: nums = [10,9,2,5,3,7,101,18] Output: 4 Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4.

Example 2:

Input: nums = [0,1,0,3,2,3] Output: 4

3 - Eliminate wasted renders

Before you get started with this task, you need to cd into the frontend directory and install dependencies

cd frontend && npm install

In frontend/src/App.tsx we have a Parent component that renders multiple child components. The issue is that the some of the child components are re-rendering when they shouldn't. Your task is to eliminate these wasted renders.