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Longest Palindromic Substring

Nov 19, 2022CodeCatch
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QM Helper

Mar 22, 2022LeifMessinger

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//QM Helper by Leif Messinger
//Groups numbers by number of bits and shows their binary representations.
//To be used on x.com
const minterms = prompt("Enter your minterms separated by commas").split(",").map(x => parseInt(x.trim()));
const maxNumBits = minterms.reduce(function(a, b) {
return Math.max(a, Math.log2(b));
});
const bitGroups = [];
for(let i = 0; i < maxNumBits; ++i){
bitGroups.push([]);
}
for(const minterm of minterms){
let outputString = (minterm+" ");
//Count the bits
let count = 0;
for (var i = maxNumBits; i >= 0; --i) {
if((minterm >> i) & 1){
++count;
outputString += "1";
}else{
outputString += "0";
}
}
bitGroups[count].push(outputString);
}
document.body.textContent = "";
document.body.style.setProperty("white-space", "pre");
for(const group of bitGroups){
for(const outputString of group){
document.body.textContent += outputString + "\r\n";
}
}

greatest common denominator

Nov 19, 2022CodeCatch

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const gcd = (...arr) => {
const _gcd = (x, y) => (!y ? x : gcd(y, x % y));
return [...arr].reduce((a, b) => _gcd(a, b));
};
gcd(8, 36); // 4
gcd(...[12, 8, 32]); // 4

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

JS Test

Mar 9, 2021LeifMessinger

0 likes • 1 view

alert("bruh")

Subsets of an array

Nov 19, 2022CodeCatch

0 likes • 2 views

const getSubsets = arr => arr.reduce((prev, curr) => prev.concat(prev.map(k => k.concat(curr))), [[]]);
// Examples
getSubsets([1, 2]); // [[], [1], [2], [1, 2]]
getSubsets([1, 2, 3]); // [[], [1], [2], [1, 2], [3], [1, 3], [2, 3], [1, 2, 3]]

Ticking clock

Nov 19, 2022CodeCatch

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function Clock(props) {
return (
<div>
<h1>Hello, world!</h1>
<h2>It is {props.date.toLocaleTimeString()}.</h2>
</div>
);
}
function tick() {
ReactDOM.render(
<Clock date={new Date()} />,
document.getElementById('root')
);
}
setInterval(tick, 1000);