Lib.rs

rotation

The idea for more efficient algorithm was derived from this stack overflow answer.

To quote from the answerer, 'Reversing three times is simplest but moves every element exactly twice, takes O(N) time and O(1) space. It is possible to circle shift an array moving each element exactly once also in O(N) time and O(1) space.'

For more info on how it adds up together, please refer to the answer (and other answers as well).

This crate exposes 2 apis, namely rotate_clock function that you will use to rotate your list clockwise, and rotate_anticlock for vice versa. below 2 examples are given to demonstrate how to use them.

Quick Start

use rotation::interface as rotator;

fn main() {
    let mut list = [1, 2, 3, 4, 5];

    let spin = 2;

    // rotate clockwise
    let rotated = rotator::rotate_clock(&mut list, spin);

    println!("{:?}", rotated); // [4, 5, 1, 2, 3];
 
    // rotate anti clockwise
    let rotated = rotator::rotate_anticlock(&mut list, spin);

    println!("{:?}", rotated); // [3, 4, 5, 1, 2];
}