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linked list

0 likes • Nov 19, 2022
JavaScript
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count substrings

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const countSubstrings = (str, searchValue) => {
let count = 0,
i = 0;
while (true) {
const r = str.indexOf(searchValue, i);
if (r !== -1) [count, i] = [count + 1, r + 1];
else return count;
}
};
countSubstrings('tiktok tok tok tik tok tik', 'tik'); // 3
countSubstrings('tutut tut tut', 'tut'); // 4

Reverse a string in Java

Test
0 likes • Nov 20, 2022
JavaScript
new StringBuilder(hi).reverse().toString()

Longest Palindromic Substring

CodeCatch
0 likes • Nov 19, 2022
JavaScript
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"))

permutations

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const permutations = arr => {
if (arr.length <= 2) return arr.length === 2 ? [arr, [arr[1], arr[0]]] : arr;
return arr.reduce(
(acc, item, i) =>
acc.concat(
permutations([...arr.slice(0, i), ...arr.slice(i + 1)]).map(val => [
item,
...val,
])
),
[]
);
};
permutations([1, 33, 5]);
// [ [1, 33, 5], [1, 5, 33], [33, 1, 5], [33, 5, 1], [5, 1, 33], [5, 33, 1] ]

getSelectedText

AustinLeath
0 likes • Nov 18, 2022
JavaScript
// Get the text that the user has selected
const getSelectedText = () => window.getSelection().toString();
getSelectedText();

Reddit Regex Comment Upvoter

ThiccDaddyLOAF
0 likes • May 17, 2021
JavaScript
//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();