function numCheck(maxVal, arr){
  for(let i = maxVal; i>=0; i--) {
    if(arr.indexOf(i) >= 0){
      return arr.indexOf(i);
    }
  }
  throw new RangeError('The inputs do not meet the requirements to create a valid time');
}

function getMaxTime(a,b,c,d){
  if(a+b+c+d > 19) {
    throw new RangeError('The inputs do not meet the requirements to create a valid time');
  }

  var arr = [a,b,c,d];
  var hourTens = arr.splice(numCheck(2,arr),1)[0];
  var hourOnes = arr.splice(numCheck(hourTens === 2 ? 3 : 9,arr),1)[0];
  var minuteTens = arr.splice(numCheck(5,arr),1)[0];
  var minuteOnes = arr.splice(numCheck(9,arr),1)[0];

  return `${hourTens}${hourOnes}:${minuteTens}${minuteOnes}`;
}