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Reverse a string in Java

Nov 20, 2022Helper
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More JavaScript Posts

Global Variables

Oct 29, 2020LeifMessinger

0 likes • 1 view

let variableSet = JSON.parse('["parent","opener","top","length","frames","closed","location","self","window","document","name","customElements","history","locationbar","menubar","personalbar","scrollbars","statusbar","toolbar","status","frameElement","navigator","origin","external","screen","innerWidth","innerHeight","scrollX","pageXOffset","scrollY","pageYOffset","visualViewport","screenX","screenY","outerWidth","outerHeight","devicePixelRatio","clientInformation","screenLeft","screenTop","defaultStatus","defaultstatus","styleMedia","onsearch",&qu...find","webkitRequestAnimationFrame","webkitCancelAnimationFrame","fetch","btoa","atob","setTimeout","clearTimeout","setInterval","clearInterval","createImageBitmap","close","focus","blur","postMessage","onappinstalled","onbeforeinstallprompt","crypto","indexedDB","webkitStorageInfo","sessionStorage","localStorage","chrome","onpointerrawupdate","speechSynthesis","webkitRequestFileSystem","webkitResolveLocalFileSystemURL","openDatabase","variableSet","TEMPORARY","PERSISTENT","addEventListener","removeEventListener","dispatchEvent"]');
let answer = [];
for(let v in this) if(!variableSet.includes(v)) answer.push(v);
console.log(answer);

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]
}
}
}
};

Flatten an array

Nov 19, 2022CodeCatch

0 likes • 1 view

const flat = arr => [].concat.apply([], arr.map(a => Array.isArray(a) ? flat(a) : a));
// Or
const flat = arr => arr.reduce((a, b) => Array.isArray(b) ? [...a, ...flat(b)] : [...a, b], []);
// Or
// See the browser compatibility at https://caniuse.com/#feat=array-flat
const flat = arr => arr.flat();
// Example
flat(['cat', ['lion', 'tiger']]); // ['cat', 'lion', 'tiger']

Reddit Regex Comment Upvoter

May 17, 2021LeifMessinger

0 likes • 2 views

//Upvotes comments according to a regex pattern. I tried it out on https://www.reddit.com/r/VALORANT/comments/ne74n4/please_admire_this_clip_precise_gunplay_btw/
//Known bugs:
//If a comment was already upvoted, it gets downvoted
//For some reason, it has around a 50-70% success rate. The case insensitive bit works, but I think some of the query selector stuff gets changed. Still, 50% is good
let comments = document.getElementsByClassName("_3tw__eCCe7j-epNCKGXUKk"); //Comment class
let commentsToUpvote = [];
const regexToMatch = /wtf/gi;
for(let comment of comments){
let text = comment.querySelector("._1qeIAgB0cPwnLhDF9XSiJM"); //Comment content class
if(text == undefined){
continue;
}
text = text.textContent;
if(regexToMatch.test(text)){
console.log(text);
commentsToUpvote.push(comment);
}
}
function upvote(comment){
console.log(comment.querySelector(".icon-upvote")); //Just showing you what it's doing
comment.querySelector(".icon-upvote").click();
}
function slowRecurse(){
let comment = commentsToUpvote.pop(); //It's gonna go bottom to top but whatever
if(comment != undefined){
upvote(comment);
setTimeout(slowRecurse,500);
}
}
slowRecurse();

Monotonic Array

Nov 19, 2022CodeCatch

0 likes • 2 views

// Time Complexity : O(N)
// Space Complexity : O(1)
var isMonotonic = function(nums) {
let isMono = null;
for(let i = 1; i < nums.length; i++) {
if(isMono === null) {
if(nums[i - 1] < nums[i]) isMono = 0;
else if(nums[i - 1] > nums[i]) isMono = 1;
continue;
}
if(nums[i - 1] < nums[i] && isMono !== 0) {
return false;
}
else if(nums[i - 1] > nums[i] && isMono !== 1) {
return false;
}
}
return true;
};
let nums1 = [1,2,2,3]
let nums2 = [6,5,4,4]
let nums3 = [1,3,2]
console.log(isMonotonic(nums1));
console.log(isMonotonic(nums2));
console.log(isMonotonic(nums3));

Longest Palindromic Substring

Nov 19, 2022CodeCatch

0 likes • 2 views

const longestPalindrome = (s) => {
if(s.length === 1) return s
const odd = longestOddPalindrome(s)
const even = longestEvenPalindrome(s)
if(odd.length >= even.length) return odd
if(even.length > odd.length) return even
};
const longestOddPalindrome = (s) => {
let longest = 0
let longestSubStr = ""
for(let i = 1; i < s.length; i++) {
let currentLongest = 1
let currentLongestSubStr = ""
let left = i - 1
let right = i + 1
while(left >= 0 && right < s.length) {
const leftLetter = s[left]
const rightLetter = s[right]
left--
right++
if(leftLetter === rightLetter) {
currentLongest += 2
currentLongestSubStr = s.slice(left+1, right)
} else break
}
if(currentLongest > longest) {
if(currentLongestSubStr) longestSubStr = currentLongestSubStr
else longestSubStr = s[i]
longest = currentLongest
}
}
return longestSubStr
}
const longestEvenPalindrome = (s) => {
let longest = 0
let longestSubStr = ""
for(let i = 0; i < s.length - 1; i++) {
if(s[i] !== s[i+1]) continue;
let currentLongest = 2
let currentLongestSubStr = ""
let left = i - 1
let right = i + 2
while(left >= 0 && right < s.length) {
const leftLetter = s[left]
const rightLetter = s[right]
left--
right++
if(leftLetter === rightLetter) {
currentLongest += 2
currentLongestSubStr = s.slice(left+1, right)
} else break
}
if(currentLongest > longest) {
if(currentLongestSubStr) longestSubStr = currentLongestSubStr
else longestSubStr = s[i] + s[i+1]
longest = currentLongest
}
}
return longestSubStr
}
console.log(longestPalindrome("babad"))