exercism/rust/magazine-cutout

Magazine Cutout

Welcome to Magazine Cutout on Exercism's Rust Track. If you need help running the tests or submitting your code, check out HELP.md. If you get stuck on the exercise, check out HINTS.md, but try and solve it without using those first :)

Introduction

Rust's entry API provides a view into a single entry in map, which may be either a HashMap or a BTreeMap. The entry may be either occupied and vacant, and the API provides methods to modify the contents of the entry.

Instructions

In this exercise you'll be using a HashMap, along with entry API methods, to solve a simple algorithm problem.

Given &[&str] representing the words of a magazine article, and &[&str] representing the words of a note you would like to send, can you compose your note by cutting words out of the magazine and pasting them into a letter?

Notes:

• This implies physical cutting and pasting; the magazine needs to contain at least as many copies of each word as the note requires.
• Capitalization matters; just because you're pasting together a note composed from words of a magazine doesn't mean you're willing to be ungrammatical.

You'll start with the following stubbed function signature:

pub fn can_construct_note(magazine: &[&str], note: &[&str]) -> bool {
    unimplemented!()
}

Given the following input

let magazine = "two times three is not four".split_whitespace().collect::<Vec<&str>>();
let note = "two times two is four".split_whitespace().collect::<Vec<&str>>();
assert!(!can_construct_note(&magazine, &note));

The function returns false since the magazine only contains one instance of "two" when the note requires two of them.

Source

Created by

• @seanchen1991