## simple_hash
### Instructions
Create a **function** named `word_frequency_counter` which will receive a vector of strings (each string being a single word) and return an `HashMap` with the word as the key and the number of repetitions as the value.
Also create a function named `nb_distinct_words` which will take a reference to the `HashMap` and return the number of distinct words present in it.
> all the words tested will be lowercase
### Expected functions
```rust
pub fn word_frequency_counter(words: Vec< & str>) -> HashMap< & str, usize> {}
pub fn nb_distinct_words(frequency_count: & HashMap< & str, usize>) -> usize {}
```
### Usage
Here is a program to test your function.
```rust
use simple_hash::*;
use std::collections::HashMap;
fn main() {
let sentence = "this is a very basic sentence with only few \
repetitions. once again this is very basic and \
but it should be enough for basic tests".to_string();
let words = sentence.split(" ").collect::< Vec < & str > >();
let frequency_count = word_frequency_counter(words);
println!("{:?}", frequency_count);
println!("{}", nb_distinct_words(&frequency_count));
}
```
And its output
```console
$ cargo run
{"tests": 1, "with": 1, "this": 2, "it": 1, "enough": 1, "is": 2, "but": 1, "sentence": 1, "only": 1, "basic": 3, "again": 1, "for": 1, "be": 1, "once": 1, "very": 2, "should": 1, "few": 1, "and": 1, "a": 1, "repetitions.": 1}
20
$
```
### Notions
- [HashMap ](https://doc.rust-lang.org/rust-by-example/std/hash.html )
