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"""

Rotate String

Given a string and an integer k, return the string rotated by k positions

to the left. Two approaches are provided.

Reference: https://en.wikipedia.org/wiki/Circular_shift

Complexity:

Time: O(n) where n is the length of the string

Space: O(n)

"""

from __future__ import annotations

def rotate(text: str, positions: int) -> str:

"""Rotate a string left by k positions using repeated string approach.

Args:

text: The string to rotate.

positions: The number of positions to rotate left.

Returns:

The rotated string.

Examples:

>>> rotate("hello", 2)

'llohe'

"""

long_string = text * (positions // len(text) + 2)

if positions <= len(text):

return long_string[positions : positions + len(text)]

else:

return long_string[positions - len(text) : positions]

def rotate_alt(string: str, positions: int) -> str:

"""Rotate a string left by k positions using modular arithmetic.

Args:

string: The string to rotate.

positions: The number of positions to rotate left.

Returns:

The rotated string.

Examples:

>>> rotate_alt("hello", 2)

'llohe'

"""

positions = positions % len(string)

return string[positions:] + string[:positions]