We are required to write a JavaScript function that takes in a number n. Our function should return an array of integers 1..n arranged in a way, such that the sum of each 2 consecutive numbers is a square.
Example
The code for this will be −
const n = 15;
const buildSquaresArray = (n = 1, res = []) => {
const helper = (res, set, n) => {
if(set.size === n){
return true;
};
for(let i = 1; i <= n; i++){
if (set.has(i)){
continue;
};
if(res.length && Math.sqrt(res[0] + i) % 1 !== 0){
continue;
};
set.add(i);
res.unshift(i);
if(helper(res,set,n)){
return true;
}
res.shift();
set.delete(i);
};
return false;
};
return helper(res,new Set(),n) ? res : false;
};
console.log(buildSquaresArray(n));Output
And the output in the console will be −
[ 9, 7, 2, 14, 11, 5, 4, 12, 13, 3, 6, 10, 15, 1, 8 ]