Reversing Array In Place

theIndianDev — Sat, 01 Jun 2019 15:05:55 +0000

Hey, hey, hey this is my first article. Gonna keep it really short. Began learning data structures and algorithms from today. I had this thought whether is there a way to reverse an array in place without using additional space (i.e. like a new array). You guessed it right, we do have a way. This is the idea:

We are going to iterate for (N/2) times (N = length of the array) and swap the first half of the array with the second half. We are only iterating n/2 times. How cool is that, let me know what you guys think.

The Code:

class Array:
  def __init__(self):
    self.array = []
    self.length = 0

  def reverse(self):
    for i in range(len(self.array)/2):
      current_position = i
      swap_position = len(self.array) - (i + 1)

      temp = self.array[swap_position]
      current_value = self.array[current_position]
      self.array[swap_position] = current_value
      self.array[current_position] = temp

    return self.array


array = Array()
array.append(1)
array.append(2)
array.append(3)
array.append(4)
array.append(5)
array.append(6)
array.append(7)
print array.reverse()

DEV Community: theIndianDev

Reversing Array In Place