… an AHashMap

as per the implementation comment on mode_on_sorted

warning: the item `Default` is imported redundantly
   --> src/frequency.rs:3:5
    |
3   | use std::default::Default;
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:125:13
    |
125 |     pub use super::v1::*;
    |             --------- the item `Default` is already defined here
    |
    = note: `#[warn(unused_imports)]` on by default

warning: the item `FromIterator` is imported redundantly
   --> src/frequency.rs:6:17
    |
6   | use std::iter::{FromIterator, IntoIterator};
    |                 ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `FromIterator` is already defined here

warning: the item `IntoIterator` is imported redundantly
   --> src/frequency.rs:6:31
    |
6   | use std::iter::{FromIterator, IntoIterator};
    |                               ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `IntoIterator` is already defined here

warning: the item `Default` is imported redundantly
   --> src/minmax.rs:1:5
    |
1   | use std::default::Default;
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:125:13
    |
125 |     pub use super::v1::*;
    |             --------- the item `Default` is already defined here

warning: the item `FromIterator` is imported redundantly
   --> src/minmax.rs:3:17
    |
3   | use std::iter::{FromIterator, IntoIterator};
    |                 ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `FromIterator` is already defined here

warning: the item `IntoIterator` is imported redundantly
   --> src/minmax.rs:3:31
    |
3   | use std::iter::{FromIterator, IntoIterator};
    |                               ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `IntoIterator` is already defined here

warning: the item `Default` is imported redundantly
   --> src/online.rs:1:5
    |
1   | use std::default::Default;
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:125:13
    |
125 |     pub use super::v1::*;
    |             --------- the item `Default` is already defined here

warning: the item `FromIterator` is imported redundantly
   --> src/online.rs:3:17
    |
3   | use std::iter::{FromIterator, IntoIterator};
    |                 ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `FromIterator` is already defined here

warning: the item `IntoIterator` is imported redundantly
   --> src/online.rs:3:31
    |
3   | use std::iter::{FromIterator, IntoIterator};
    |                               ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `IntoIterator` is already defined here

warning: the item `Default` is imported redundantly
   --> src/unsorted.rs:3:5
    |
3   | use std::default::Default;
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:125:13
    |
125 |     pub use super::v1::*;
    |             --------- the item `Default` is already defined here

warning: the item `FromIterator` is imported redundantly
   --> src/unsorted.rs:4:17
    |
4   | use std::iter::{FromIterator, IntoIterator};
    |                 ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `FromIterator` is already defined here

warning: the item `IntoIterator` is imported redundantly
   --> src/unsorted.rs:4:31
    |
4   | use std::iter::{FromIterator, IntoIterator};
    |                               ^^^^^^^^^^^^
    |
   ::: /Users/joelnatividad/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/prelude/mod.rs:129:13
    |
129 |     pub use core::prelude::rust_2021::*;
    |             ------------------------ the item `IntoIterator` is already defined here

warning: `qsv-stats` (lib) generated 12 warnings

- Use just one vec for both values and modes
- change it to compile modes in a single pass, not two passes like before

…ever fail

as we do not use it in qsv