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Invert Binary Tree

Oct 15, 2022CodeCatch
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More JavaScript Posts

euclidean distance

Nov 19, 2022CodeCatch

0 likes • 3 views

const euclideanDistance = (a, b) =>
Math.hypot(...Object.keys(a).map(k => b[k] - a[k]));
euclideanDistance([1, 1], [2, 3]); // ~2.2361
euclideanDistance([1, 1, 1], [2, 3, 2]); // ~2.4495

LeetCode Two Sum

Sep 13, 2023C S

0 likes • 2 views

/**
* @param {number[]} nums
* @param {number} target
* @return {number[]}
*/
var twoSum = function(nums, target) {
for(let i = 0; i < nums.length; i++) {
for(let j = 0; j < nums.length; j++) {
if(nums[i] + nums[j] === target && i !== j) {
return [i, j]
}
}
}
};

Scrape twitter

Sep 2, 2023LeifMessinger

0 likes • 10 views

//Allegedly never tested on the twitter website
function scrapeScreen(){
let articles = Array.from(document.getElementsByTagName("article"));
let results = [];
for(let tweet of articles){
const isAnAd = Array.from(tweet.querySelectorAll("span")).map((e)=>e.textContent).includes("Ad");
if(isAnAd){
//console.log(tweet, "is an ad. Skipping...");
continue;
}
const userName = tweet.querySelector("[data-testid='User-Name'] > div:nth-child(2) > div > div")?.textContent;
const tweetContent = tweet.querySelector("[data-testid='tweetText']")?.textContent;
const timeStamp = tweet.querySelector("time")?.getAttribute("datetime");
const tweetLink = tweet.querySelector("time")?.parentElement?.getAttribute("href");
if((!userName) || (!tweetContent)) continue;
results.push({
username: userName,
tweetText: tweetContent,
timeStamp: timeStamp,
tweetLink: tweetLink
});
}
return results;
}
let scraped = scrapeScreen();
setInterval(()=>{
scraped = scraped.concat(
scrapeScreen().filter((tweet)=>{
for(let scrapedTweet of scraped){
if(scrapedTweet.username == tweet.username && scrapedTweet.tweetText == tweet.tweetText) return false;
}
return true;
})
);
}, 500); //Scrape everything on the screen twice a second
window.scrollIntervalId = setInterval(function(){
window.scrollBy(0, 1000);
}, 500); //Scroll for me
//http://bgrins.github.io/devtools-snippets/#console-save
(function(console){
console.save = function(data, filename){
if(!data) {
console.error('Console.save: No data')
return;
}
if(!filename) filename = 'console.json'
if(typeof data === "object"){
data = JSON.stringify(data, undefined, '\t')
}
var blob = new Blob([data], {type: 'text/json'}),
e = document.createEvent('MouseEvents'),
a = document.createElement('a')
a.download = filename
a.href = window.URL.createObjectURL(blob)
a.dataset.downloadurl = ['text/json', a.download, a.href].join(':')
e.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null)
a.dispatchEvent(e)
}
})(console)
setTimeout(()=>{
clearTimeout(window.scrollIntervalId);
delete window.scrollIntervalId;
console.save(scraped, "TwitterScrape" + Date.now() + ".json");
}, 60 * 1000 * 20); //Twenty minutes

linked list

Nov 19, 2022CodeCatch

0 likes • 1 view

class LinkedList {
constructor() {
this.nodes = [];
}
get size() {
return this.nodes.length;
}
get head() {
return this.size ? this.nodes[0] : null;
}
get tail() {
return this.size ? this.nodes[this.size - 1] : null;
}
insertAt(index, value) {
const previousNode = this.nodes[index - 1] || null;
const nextNode = this.nodes[index] || null;
const node = { value, next: nextNode };
if (previousNode) previousNode.next = node;
this.nodes.splice(index, 0, node);
}
insertFirst(value) {
this.insertAt(0, value);
}
insertLast(value) {
this.insertAt(this.size, value);
}
getAt(index) {
return this.nodes[index];
}
removeAt(index) {
const previousNode = this.nodes[index - 1];
const nextNode = this.nodes[index + 1] || null;
if (previousNode) previousNode.next = nextNode;
return this.nodes.splice(index, 1);
}
clear() {
this.nodes = [];
}
reverse() {
this.nodes = this.nodes.reduce(
(acc, { value }) => [{ value, next: acc[0] || null }, ...acc],
[]
);
}
*[Symbol.iterator]() {
yield* this.nodes;
}
}
const list = new LinkedList();
list.insertFirst(1);
list.insertFirst(2);
list.insertFirst(3);
list.insertLast(4);
list.insertAt(3, 5);
list.size; // 5
list.head.value; // 3
list.head.next.value; // 2
list.tail.value; // 4
[...list.map(e => e.value)]; // [3, 2, 1, 5, 4]
list.removeAt(1); // 2
list.getAt(1).value; // 1
list.head.next.value; // 1
[...list.map(e => e.value)]; // [3, 1, 5, 4]
list.reverse();
[...list.map(e => e.value)]; // [4, 5, 1, 3]
list.clear();
list.size; // 0

find primes

Nov 19, 2022CodeCatch

0 likes • 0 views

const primes = num => {
let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2),
sqroot = Math.floor(Math.sqrt(num)),
numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2);
numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y === x)));
return arr;
};
primes(10); // [2, 3, 5, 7]

LeetCode Product Except Self

Sep 13, 2023C S

0 likes • 11 views

/**
* @param {number[]} nums
* @return {number[]}
*/
var productExceptSelf = function(nums) {
var output = [];
var leftMult = 1;
var rightMult = 1;
for (var i=nums.length - 1; i >= 0; i--) {
output[i] = rightMult;
rightMult *= nums[i];
console.log({output: JSON.stringify(output), i})
}
for (var j=0; j < nums.length; j++) {
output[j] *= leftMult;
leftMult *= nums[j];
console.log({output: JSON.stringify(output), j})
}
return output;
};
console.log(productExceptSelf([1, 2, 3, 4]))