open-day-solutions

open-day-solutions.js

var getChange = (cost, sum) => {
  let rem = Math.round((sum - cost) * 100);
  return [100, 50, 20, 10, 5, 1].map(v => {
    let n = ~~(rem / v);
    rem -= n * v;
    return n; 
  }).reverse();
}

var zoom = (n, f=v=>Math.min(v,n-v-1)) =>
  Array.from({ length: n }).map((_, x) =>
    Array.from({ length: n }).map((_, y) =>
      Math.min(f(x), f(y)) % 2 ? '□' : '■'
    ).join('')
  ).join('\n');