DD1337 Week 2

Author: Viola Söderlund
Modified by: Isak Larsson

Getting started

Install Rust

1. Install Rustup.
2. If you're running Windows, install Visual Studio C++ Build Tools.
3. If you're developing in Visual Studio Code, install the superior Rust extension.

Prepare for your assigment

Your first assignment is turned in by uploading it to a repository named <KTH_ID>-task-2 (ex. isaklar-task-2) under the INDAPlus22 organisation. Be careful to get the spelling right.

The grade to an assigment is left in the form of an issue with "Pass", "Komplettering", or "Fail" in the title. In case of "Komplettering", read the instructions on what to adjust down in the issue description. Leave a comment on the issue upon reupload of the assignment. "Pass" and "Fail" are self explanatory.

1. Create a repository named <KTH_ID>-task-2.
2. Clone your newly created repository. git clone [email protected]:INDAPlus21/<KTH_ID>-task-2.git
3. Create one Rust crate (term for application or library) per subassignment.

How to create a Rust application (binary) crate

1. Navigate in your terminal or command prompt to <KTH_ID>-task-2.
2. Initialise your Rust crate. cargo init <crate_name>
3. Navigate into your newly created root directory.
4. Build and run your application. cargo run

Your clean build should look like:

appropriate_name
|- src
  |- main.rs
|- target
|- Cargo.lock
|- Cargo.toml

Write your source code in src, where the main function is located in src/main.rs. To make it easier, begin by copying the contents of ./kattis_template/src/main.rs into your main.rs file.

Assignment

Kattis problems

This week, you're going to learn the basics of Rust by solving easier Kattis problems. For each problem, create one Rust crate in your repo. Include a screenshot of your Kattis submission to prove solution. See ./minimal_scalar_product for a Kattis solution example.

Solve at least two of the following problems:

• Summera tal
• Avstånd till kanten
• Cyber-Clara och anmälningslistorna
• A Different Problem

(optional fun):

• Game Rank
• Quantum

(optional challenge):

• Cyber-Clara och anmälningslistorna is a special problem. The Rust statistics board is littered with +- and ++-students. Take them down!
• A example solution to the Kattis problem Minimal Scalar Product can be found in ./minimal_scalar_product. This solution runs at 0.06s. See the statistics for the Rust language. As you can see, it's possible to solve this problem in much less time. Write your own solution, which may be based on the example solution, and which runs quicker than 0.06s.

Questions

Be prepared to answer the following questions during the next övning.

Method chaining

Observe the following code:

let input = io::stdin();

let mut lines = input
    .lock()
    .lines()
    .map(|_line| _line.ok().unwrap().to_string());

// for every line, assuming input strings with the characters '0' and '1' seperated by whitelines

let binary_line = lines
    .next().unwrap()
    .split(" ")
    .map(|_title| {
        _title
            .chars()
            .map(|_character| {
                match _character {
                    '0' => false,
                    _ => true
                }
            })
            .collect::<Vec<bool>>()
    })
    .collect::<Vec<Vec<bool>>>();

Know the answer of the following question:

• What is the value of binary_line?

Iterables

Observe the following code:

use std::collections::{ HashMap, HashSet };

/*...*/

let limit: usize = 10;

let mut index_store: HashMap<usize, usize> = HashMap::with_capacity(limit + 1);
let mut value_store: Vec<HashSet<usize>> = Vec::with_capacity(limit + 1);
        
for value in 1..(limit + 1) {
    index_store.insert(value, value - 1);

    let mut sequence: HashSet<usize> = HashSet::new();
    sequence.insert(value);

    value_store.push(sequence);
}

Know the answer of the following questions:

• What is the value of index_store?
• What is the value of value_store?