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  1. Practice
  2. Data Structures
  3. Arrays
  4. Left Rotation
  5. Discussions

Left Rotation

  • akshayd31 + 5 comments

    My solution in Python:

    n,d = map(int, raw_input().strip().split()) arr = map(int, raw_input().strip().split())

    print ' '.join(str(s) for s in (arr[d:] + arr[0:d]))

    • polmki99 + 2 comments

      Very similar to my code. I took the modulus of d but it isn't really necessary because the slice method does it automatically.

      n, d = map(int, input().strip().split())
arr = list(map(int, input().strip().split()))

d %= n
print(*(arr[d:] + arr[:d]))
      • Xarmanla + 0 comments

        Looks the same as the one I wrote before looking at the discussion. As a person who programmed bit sliced arrays, I love python.

      • talktofreeman + 0 comments

        nd = input().split()

        n = int(nd[0])

d = int(nd[1])

a = list(map(int, input().rstrip().split()))

l= [1,2,3,4,5,6,7,8,9]
i=0
while i<len(a):
    print (a[(i+d)%len(a)], end = ' ')
    i+=1
    • NotQuantum + 0 comments

      arr[0:d] you don't need the 0

    • florent_moiny + 1 comment

      Smart move to slice, hadn't thought about it. One way to improve your code (because I had the same issue): you need to use the generator expression 

      ' '.join(str(s) for s in (arr[d:] + arr[0:d]))

      because you applied the int function to your input. Don't do that and it becomes easier:

      n,d = map(int, raw_input().strip().split())
arr = raw_input().strip().split()
print ' '.join(arr[d:] + arr[0:d])

      Also, I wouldn't mind an if n == d, but that's just my point of view here.

      • freddie71010 + 0 comments

        Looks great, my python solution printed an unzipped list.

        # separates n and d values into two variables
n, d = [int(x) for x in input().split()]
# creates list of integers
lst = [int(x) for x in input().split()]

# From inner most function to outermost=============
# creates a list using lst[d:] and combines it with lst[0:d]
# unzips list (* = unzips)
# prints list
print(*(lst[d:]+lst[0:d]))
    • christine_e_hill + 0 comments

      Maybe I am being pendantic, but since the instructions said to "Print a single line of space-separated integers", I thought we were supposed to print them as integers.

      So I used:

      for n in arr: print n,

      Still trying to think of an instance in which this distinction would matter...

    • yangAnn + 4 comments

      I thought my solution is neat. but here are more neat solutions!

      n, d = map(int, input().strip().split())
arr = [int(arr_t) for arr_t in input().strip().split()]
for _ in range(d):
    arr.append(arr.pop(0))
print (*arr)
      • freddie71010 + 0 comments

        Great solution!

      • AffineStructure + 0 comments

        Hey, I like your solution. A recommendation for the future is if you want to pop the first element, you should use a deque. https://docs.python.org/3/library/collections.html#collections.deque

        arr.pop(0) is O(N) while the deque version arr.popleft() is O(1)

      • AatmanMantri + 1 comment

        Hey! Can you tell me how does *arr work?

        • AffineStructure + 0 comments

          https://pythontips.com/2013/08/04/args-and-kwargs-in-python-explained/

      • whtiger + 0 comments

        good one!