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export const checkSudoku = (board) => {
  for (let i = 0; i < 4; i++) {
    const row = new Set();
    const col = new Set();
    const square = new Set();
    for (let j = 0; j < 4; j++) {
      const rowEl = board[i][j];
      const colEl = board[j][i];
      const squareEl =
        board[2 * Math.floor(i / 2) + Math.floor(j / 2)][2 * (i % 2) + (j % 2)];

danny-andrews

Shell Command Structure Summary

Arguments (i.e. Positional Arguments)

Positional arguments are passed as-is after the command name. Order matters.

cat file1.txt file2.txt

---

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import esbuild from "esbuild";
import { readFile } from "node:fs/promises";
import { fileURLToPath } from "node:url";

export async function load(url, context, nextLoad) {
  const source = await readFile(fileURLToPath(url), "utf-8");

  if (/\.jsx$/.test(url)) {
    const transformedSource = await esbuild.transform(source, {
      loader: "jsx",

danny-andrews

Install SQL using Homebrew

Begin by updating brew:

brew update

To install the latest version of PostgreSQL using Homebrew, run the following commands.

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Postgres Setup on WSL

1. Download Postgres: sudo apt install postgresql.
2. NOTE: Restart your terminal if you already have it open. And if you're using the terminal in VSCode, you'll have to restart VSCode to have it pick up the changes to the PATH variable.
3. Run $ psql -U postgres in command prompt. This runs the psql command as the default "postgres" superuser.
4. Run: postgres=# CREATE USER "[WINDOWS_USERNAME]" WITH PASSWORD '[PASSWORD]' SUPERUSER;
5. Quit postgres: postgres=# \q
6. Run psql postgres and type the password you used in the CREATE USER command

Starting/Stopping/Restarting postgres: https://stackoverflow.com/a/53062239

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Cheat sheet: JavaScript Array methods

Finding Array elements:

['■', '●', '■'].includes('■')           ⟼ true
['■', '●', '■'].indexOf('■')            ⟼ 0
['■', '●', '■'].lastIndexOf('■')        ⟼ 2
['■', '●', '■'].find(x => x==='■')      ⟼ '■'
['■', '●', '■'].findIndex(x => x==='■') ⟼ 0

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/**
 * Implement a function that finds the longest palindrome in a given string.
 * For example, in the string "My dad is a racecar athlete", the longest
 * palindrome is "a racecar a". Count whitespaces as valid characters. Other
 * palindromes in the above string include "dad", "ete", " dad " (including
 * whitespace on each side of dad).
 */

function longestPalindrome(string) {}

danny-andrews

MongoDB Quickstart

Introduction

1. Read: https://docs.mongodb.com/manual/introduction/
2. Read: https://docs.mongodb.com/manual/crud/

Installation

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class Node {
  constructor(data) {
    this.data = data;
    this.left = null;
    this.right = null;
  }
}

// Every value in the Left subtree less than root
// Every value in the right subtree is greater than or equal to the root

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const reverseIterative = (arr) => {
  const result = [];
  for (let i = arr.length - 1; i >= 0; i--) {
    result.push(arr[i]);
  }

  return result;
};

const reverseRec = (arr) =>