public static void bubbleSort(int[] arr) {
    var lastIndex = arr.length - 1;

    for(var j = 0; j < lastIndex; j++) {
      for(var i = 0; i < lastIndex - j; i++) {
        if(arr[i] > arr[i + 1]) {
          var tmp = arr[i];
          arr[i] = arr[i + 1];
          arr[i + 1] = tmp;
        }
      }
    }
  }