Ruby:
def wave_sort(arr) arr.sort!
(1..arr.length-1).step(2) do |i| arr[i], arr[i-1] = arr[i-1], arr[i] end
arr end
JS:
function waveSort(arr) { arr.sort((a,b) => a - b);
for (let i = 1; i < arr.length; i += 2) { [arr[i], arr[i-1]] = [arr[i-1], arr[i]]; }
return arr; }