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Time complexity of Array Slicing and Simultaneous Assignment

Questions : Time complexity of Array Slicing and Simultaneous Assignment

2022-09-22T19:58:23+00:00 2022-09-22T19:58:23+00:00

Table of Contents

• Time complexity of Array Slicing and Simultaneous Assignment
• Questions : Time complexity of Array Slicing and Simultaneous Assignment
• Answers 1 : of Time complexity of Array Slicing and Simultaneous Assignment
• Description¶
• Return Value¶
• Time Complexity¶
• Example 1¶
• Example 2¶
• Example 3¶
• Example 4¶
• Example 5¶
• Example 6¶
• Example 7¶
• Example 8¶
• Is slicing constant time?
• Is Len O 1 Python?
• What is the time complexity of slicing in Python?
• Is Python slicing inclusive?

665

I'm working on a leetcode problem where you anycodings_time-complexity rotate an array.

"Given an array, rotate the array to the anycodings_time-complexity right by k steps, where k is non-negative."

In the solution I'm trying, I slice the anycodings_time-complexity array, getting the last k elements and the anycodings_time-complexity first n-k elements. This is stored in a anycodings_time-complexity tuple, then assigned to the first k elements anycodings_time-complexity and last n-k elements, respectively (code anycodings_time-complexity shown below).

Is this solution O(1) time and O(1) space, anycodings_time-complexity or does the slicing operation and anycodings_time-complexity tuple/simultaneous assignment have extra anycodings_time-complexity time/space costs that I'm not aware of?

def rotate(self, nums: List[int], k: int) -> None:

    k = k% len(nums)

        if k>0:
    nums[:k],nums[k:] = nums[-k:], nums[:-k]

Total Answers 1

29

Answers 1 : of Time complexity of Array Slicing and Simultaneous Assignment

As said here Big-O of list slicing , anycodings_arrays array slicing in Python is not in O(1) anycodings_arrays since it's backed by an array behind.

Your algorithm would therefore be in anycodings_arrays O(k) since you read k elements 2 times anycodings_arrays and write k elements 2 times to your anycodings_arrays array.

0

2022-09-22T19:58:23+00:00 2022-09-22T19:58:23+00:00Answer Link

mRahman

Description¶

Gives access to a specified range of sequence’s elements.

Syntax¶

sequence [start:stop[:step]]

Return Value¶

The same as selected.

Time Complexity¶

O(k) for slice retrieval

O(n) for deletion

O(n+k) for slice assignment

Example 1¶

It can be read as: get every single one item between indexes 0 and 2 (exclusive).

The next example shows usage of the step argument:

Example 2¶

That can be interpreted as: get every second element between indexes 0 and 4.

Usage of start, stop and step operators is optional:

Example 3¶

>>> "ABCD"[1:]
'BCD'
>>> "ABCD"[:3]
'ABC'
>>> "ABCD"[1:3]
'BC'
>>> "ABCD"[1:3:]
'BC'
>>> "ABCD"[::2]
'AC'
>>> "ABCD"[::]
'ABCD'
>>> "ABCD"[:]
'ABCD'

Negative step argument can be used to reverse the sequence:

Example 4¶

>>> "ABCD"[::-1]
'DCBA'
>>> [0, 1, 2, 3][::-1]
[3, 2, 1, 0]

Example 5¶

>>> # slices can be used to replace multiple items
>>> l = [0, 1, 2, 3]
>>> l[:2] = ("AB", "CD")
>>> l
['AB', 'CD', 2, 3]

Example 6¶

>>> l = [0, 1, 2, 3]
>>> l[1:2] = (7, 8, 9, 10)
>>> l
[0, 7, 8, 9, 10, 2, 3]

Example 7¶

>>> # when using extended slice syntax both chunks must match
>>> l = [0, 1, 2, 3]
>>> l[::2] = "ABCD"
Traceback (most recent call last):
  File "<interactive input>", line 1, in <module>
ValueError: attempt to assign sequence of size 4 to extended slice of size 2

Example 8¶

>>> # deleting items
>>> l = [0, 1, 2, 3]
>>> del l[::2]
>>> l
[1, 3]

Is slicing constant time?

Slicing is a constant time operation. A slice header contains the pointer to the underlying array, size, and capacity.

Is Len O 1 Python?

Hence, len() function in Python runs in O(1) complexity. Note: This might seem very beneficial, but remember that it puts a remarkable burden on the interpreter during the data definition phase. This is one of the many reasons why Python is slower during competitive programming, especially with big inputs.

What is the time complexity of slicing in Python?

the time complexity of slicing in python is O(k) please visit https://wiki.python.org/moin/TimeComplexity#list for more. the learning experience you deserve. the doubt. O(n) where n is the length of the slice.

Is Python slicing inclusive?

Python is a zero-indexed language (things start counting from zero), and is also left inclusive, right exclusive you are when specifying a range of values. This applies to objects like lists and Series , where the first element has a position (index) of 0.