aryairani

Take-home functional programming interview

This document is licensed CC0.

These are some questions to give a sense of what you know about FP. This is more of a gauge of what you know, it's not necessarily expected that a single person will breeze through all questions. For each question, give your answer if you know it, say how long it took you, and say whether it was 'trivial', 'easy', 'medium', 'hard', or 'I don't know'. Give your answers in Haskell for the questions that involve code.

Please be honest, as the interviewer may do some spot checking with similar questions. It's not going to look good if you report a question as being 'trivial' but a similar question completely stumps you.

Here's a bit more guidance on how to use these labels:

aryairani

- job: homebrew_template
  dependsOn: multi_build
  steps:
  - task: DownloadBuildArtifacts@0
  # https://docs.microsoft.com/en-us/azure/devops/pipelines/tasks/utility/download-build-artifacts
    inputs:
      buildType: current
      downloadType: specific
  - script: |
      osxhash=`shasum -a 256 $osxpkg | cut -d " " -f 1`

aryairani

.> pull https://github.com/unisonweb/base_v2:.trunk .base

  Here's what's changed in .base after the merge:
  
  Added definitions:
  
    1.    unique type ANSI.Color
    2.    ability Abort (+2 metadata)
    3.    builtin type Any

aryairani

2021-05-12T01:43:07.8532430Z ##[section]Starting: Request a runner to run this job
2021-05-12T01:43:08.0378711Z Can't find any online and idle self-hosted runner in current repository that matches the required labels: 'ubuntu-18.04'
2021-05-12T01:43:08.0378831Z Can't find any online and idle self-hosted runner in current repository's account/organization that matches the required labels: 'ubuntu-18.04'
2021-05-12T01:43:08.0379037Z Found online and idle hosted runner in current repository's account/organization that matches the required labels: 'ubuntu-18.04'
2021-05-12T01:43:08.1876815Z ##[section]Finishing: Request a runner to run this job
2021-05-12T01:43:16.7080880Z Current runner version: '2.278.0'
2021-05-12T01:43:16.7108834Z ##[group]Operating System
2021-05-12T01:43:16.7109807Z Ubuntu
2021-05-12T01:43:16.7110333Z 18.04.5
2021-05-12T01:43:16.7110775Z LTS

aryairani

arya@jrrr unison % stack exec unison -- -codebase c --old-codebase init
Initializing a new codebase in: /Users/arya/unison/c
arya@jrrr unison % stack exec unison -- -codebase c --old-codebase     

  I've started a codebase API server at 


  http://127.0.0.1:54494?eeMzm4cguksvi%2BbS3XADleeMUOmLTD64

aryairani

2020-06-01 12:00:14.741795 [ThreadId 5] - 




haskell-lsp:Starting up server ...
2020-06-01 12:00:14.750066 [ThreadId 5] - ---> {"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":28616,"rootPath":"/Users/arya/unison/master/","rootUri":"file:///Users/arya/unison/master/","workspaceFolders":[],"capabilities":{"workspace":{"applyEdit":true,"configuration":false,"workspaceEdit":{"documentChanges":true},"workspaceFolders":false,"didChangeConfiguration":{"dynamicRegistration":false},"didChangeWatchedFiles":{"dynamicRegistration":false},"symbol":{"dynamicRegistration":false},"executeCommand":{"dynamicRegistration":false}},"textDocument":{"synchronization":{"dynamicRegistration":false,"willSave":true,"willSaveWaitUntil":true,"didSave":true},"completion":{"dynamicRegistration":false,"completionItem":{"snippetSupport":true,"commitCharactersSupport":false},"contextSupport":true},"hover":{"dynamicRegistration":false},"signatureHelp":{"dynamicRegistration":false},"references":{"dynamicRegistration":false

aryairani

  Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Signal/1.33.4 Chrome/80.0.3987.163 Electron/8.2.1 Safari/537.36 node/12.13.0 env/production
  INFO  2020-05-21T16:57:39.374Z app ready
  INFO  2020-05-21T16:57:39.375Z starting version 1.33.4
  INFO  2020-05-21T16:57:39.399Z updateSchema:
    Current user_version: 20;
    Most recent db schema: 20;
    (deprecated) schema_version: 77;

  INFO  2020-05-21T16:57:39.778Z Initializing BrowserWindow config: {"show":true,"width":832,"height":550,"minWidth":680,"minHeight":550,"autoHideMenuBar":false,"backgroundColor":"#3a76f0","webPreferences":{"nodeIntegration":false,"nodeIntegrationInWorker":false,"contextIsolation":false,"preload":"/Applications/Signal.app/Contents/Resources/app.asar/preload.js","nativeWindowOpen":true,"spellcheck":true},"icon":"/Applications/Signal.app/Contents/Resources/app.asar/build/icons/png/512x512.png","x":0,"y":23}
  INFO  2020-05-21T16:57:39.978Z spellcheck: user locale: en-US

aryairani

With -O2 accidentally

changes to SlimCopy..hs	MB*s
no change	329.2
State.Strict	230.9
Writer.Strict	176.3
Writer.Strict + State.Strict	176.5
Index	386.9
Index + Map.Strict	321.7
Index + State.Strict	230.6

aryairani

✔ ~/unison/pt/1408-numbered [pt/1408-numbered|…770] 
12:57 $ cabal v2-run unison
Up to date

   _____     _             
  |  |  |___|_|___ ___ ___ 
  |  |  |   | |_ -| . |   |
  |_____|_|_|_|___|___|_|_|
  
  Welcome to Unison!

aryairani

ndnd:tmp arya$ git init --bare repo.git
Initialized empty Git repository in /private/tmp/repo.git/
ndnd:tmp arya$ git clone repo.git 1
Cloning into '1'...
warning: You appear to have cloned an empty repository.
done.
ndnd:tmp arya$ git clone repo.git 2
Cloning into '2'...
warning: You appear to have cloned an empty repository.
done.