# permute

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Generate permutations of a slice in a memory-efficient and deterministic manner, using
[Heap's algorithm](https://en.wikipedia.org/wiki/Heap%27s_algorithm).

For instance, printing all the permutations of the sequence ["red", "green",
"blue"]:

```rust
use permute::permutations_of;

for permutation in permutations_of(&["red", "green", "blue"]) {
    for element in permutation {
        print!("{}, ", element);
    }
    println!("");
}
```

Based on the ordering provided by Heap’s algorithm, it’s guaranteed that this
program will produce:

```text
red, green, blue,
green, red, blue,
blue, red, green,
red, blue, green,
green, blue, red,
blue, green, red,
```

This crate also provides the `ArbitraryTandemControlIter`, which allows
iterating over a slice using a slice of indices - that's how Heap's algorithm is
implemented here.