/**
 * @param {number} x
 * @return {number}
 */
var reverse = function(x) {
  var sign = 1;
  var magnitude = 1;
  var reverse = 0;
  var digits = [];
  
  if (x < 0){
    sign = -1;
    x = x * sign;
  }
  
  if (x === 0){
    return reverse;
  }
  
  while (x > 0){
    digits.push(getTensDigit(x));
    x = popDigit(x);
  }
  
  for (var i = digits.length -1; i >= 0; --i){
    reverse += (digits[i] * magnitude);
    magnitude *= 10;
  }
  
  if (reverse > 2147483647){
    return 0;
  }
  
  reverse = reverse * sign;
  
  return reverse;
};

function getTensDigit(value){
  var digit = value % 10;
  return digit;
}

function popDigit(value){
  value = Math.floor(value / 10);
  return value;
}