solution.md

Solution

{{#include exercise.rs:solution}}

The solution demonstrates the power of iterator method chaining to express complex logic concisely:

• Infinite Iteration: cycle() creates an iterator that repeats the input indinitely, elegantly handling the wraparound requirement without modulo arithmetic.
• Iterator Composition: zip() combines the original and offset iterators. It naturally terminates when the shorter (finite) iterator is exhausted.
• Functional Transformation: map() applies the subtraction, and collect() performs the final transformation back into a Vec.

Details

• Laziness: Iterator chains are lazy. No work is done until a terminal operation like collect() is called. The compiler is often able to optimize these chains into a single tight loop that is as efficient as imperative code.
• Reference Handling: Note that values.iter() yields references (&i32). In the map closure, we use the dereference operator (*) to access the underlying values for arithmetic.