Compilare: warning: unused import: `std::collections::HashMap` --> main.rs:1:5 | 1 | use std::collections::HashMap; | ^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `#[warn(unused_imports)]` on by default warning: unused import: `std::ops::Add` --> main.rs:5:5 | 5 | use std::ops::Add; | ^^^^^^^^^^^^^ warning: unused variable: `n` --> main.rs:135:9 | 135 | let n = sf.next_u32().unwrap(); | ^ help: if this is intentional, prefix it with an underscore: `_n` | = note: `#[warn(unused_variables)]` on by default warning: 3 warnings emitted