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Ticking clock

0 likes • Nov 19, 2022
JavaScript
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Convert data to yyyy mm dd format

CodeCatch
0 likes • Nov 19, 2022
JavaScript
// `date` is a `Date` object
const formatYmd = date => date.toISOString().slice(0, 10);
// Example
formatYmd(new Date()); // 2020-05-06

Check if array is empty

CodeCatch
0 likes • Nov 19, 2022
JavaScript
arr = [] // empty array
const isEmpty = arr => !Array.isArray(arr) || arr.length === 0;
// Examples
isEmpty([]); // true
isEmpty([1, 2, 3]); // false

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"))

greatest common denominator

CodeCatch
0 likes • Nov 19, 2022
JavaScript
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
function printHeap(heap, index, level) {
if (index >= heap.length) {
return;
}
console.log(" ".repeat(level) + heap[index]);
printHeap(heap, 2 * index + 1, level + 1);
printHeap(heap, 2 * index + 2, level + 1);
}
//You can call this function by passing in the heap array and the index of the root node, which is typically 0, and level = 0.
let heap = [3, 8, 7, 15, 17, 30, 35, 2, 4, 5, 9];
printHeap(heap,0,0)

Destructuring Assignment

CodeCatch
0 likes • Nov 19, 2022
JavaScript
//JavaScript program to swap two variables
//take input from the users
let a = prompt('Enter the first variable: ');
let b = prompt('Enter the second variable: ');
//using destructuring assignment
[a, b] = [b, a];
console.log(`The value of a after swapping: ${a}`);
console.log(`The value of b after swapping: ${b}`);