public/subjects/insertion_sort/README.md

## insertion_sort

### Instructions

- Implement the insertion sort algorithm by creating a function `insertion_sort(slice, steps)` which executes the iterations of the algorithm **up to** the number of steps indicated by the parameter `steps`. See the **Usage** for more information.

The insertion sort algorithm to sort an array of size n in ascending order:

1. Iterates from slice[1] to slice[n] over the slice.

2. Compares the current element (key) to its predecessor.

3. If the key element is smaller than its predecessor, compares it to the elements before. Move the greater elements one position up to make space for the swapped element.

Here is a visual example of sorting a slice step by step using the insertion sort algorithm.

![image.png](Insertion-Sort-demo.png)

**Figure 1** - Step by step execution of the algorithm insertion sort

### Expected Function

```rust
pub fn insertion_sort(slice: &mut [i32], steps: usize) {

}
```

### Usage

Here is a possible program to test your function,

```rust
fn main() {
    let mut target = [5, 3, 7, 2, 1, 6, 8, 4];
    // executes the first iteration of the algorithm
    insertion_sort(&mut target, 1);
    println!("{:?}", target);

    let mut target = [5, 3, 7, 2, 1, 6, 8, 4];
    let len = target.len();
    // executes len - 1 iterations of the algorithm
    // i.e. sorts the slice
    insertion_sort(&mut target, len - 1);
    println!("{:?}", target);
}
```

And its output:

```console
$ cargo run
[3, 5, 7, 2, 1, 6, 8, 4]
[1, 2, 3, 4, 5, 6, 7, 8]
$
```