A rust implementation of a Shuffle Vector, as described by https://beta.observablehq.com/@jobleonard/shuffle-vectors.
As items are pushed to the Shuffle Vector, they are swapped with a random element (which could include themself). Popping an element from the end therefore gives a random item. This is useful when you want to draw from a random bag in O(1).
let mut v = ShuffleVector::new (vec!());
v.push(1); // [1]
v.push(2); // [2, 1]
v.push(3); // [2, 3, 1]
v.push(4); // [4, 3, 1, 2]
v.push(5); // [4, 3, 5, 2, 1]
dbg!(v.clone()); // [4, 3, 5, 2, 1]
dbg!(v.pop()); // 1
dbg!(v.pop()); // 2
dbg!(v.pop()); // 5
dbg!(v.clone()); // [4, 3]