Reddit Daily Programmer - Challenge #353 [Intermediate]

pancakes.rs

//A program for the r/dailyprogrammer challenge #353 [Intermediate], done using Rust.

use std::io;

fn main() {
    println!("Let's get the pancakes sorted!");
    println!("----");
    loop {
        let num: usize = get_input().parse().expect("Enter only numbers");
        let pancakes = get_input();
        let sorted_pancakes = sort_pancakes(num, pancakes);
        println!("{} flips: {}", sorted_pancakes.0, sorted_pancakes.1);
        println!("----");
    }
}

fn get_input() -> String {
    //Get user input
    let mut input = String::new();
    io::stdin().read_line(&mut input)
        .expect("Failed to read line");
    input.trim().to_string()
}

fn sort_pancakes_asc(num: usize, raw_pancakes: String) -> (usize, Vec<Vec<usize>>) {
    //Split pancakes
    let mut pancakes: Vec<usize> = vec!();
    for pancake in raw_pancakes.split(" ") {pancakes.append(&mut vec!(pancake.parse().expect("Error: only enter numbers")));}
    let mut flips: usize = 0;
    let mut steps: Vec<Vec<usize>> = vec!();
    for i in (1..num+1).rev() {
        while match pancakes[..i].iter().max() {Some(max) => max, None => &0} != &pancakes[i-1] {
            if &pancakes[0] == match pancakes[..i].iter().max() {Some(max) => max, None => &0} {
                //Pancake is in beginning, flip
                let mut flipped_pancakes: Vec<usize> = pancakes[..i].iter().rev().cloned().collect();
                let mut other_pancakes: Vec<usize> = pancakes[i..].to_vec();
                flipped_pancakes.append(&mut other_pancakes);
                pancakes = flipped_pancakes.clone();
                steps.append(&mut vec!(flipped_pancakes));
            } else {
                //Bring pancake to beginning
                let i_max = pancakes.iter().enumerate().find(|&r| r.1 == match pancakes[..i].iter().max() {Some(max) => max, None => &0}).unwrap().0;
                let mut flipped_pancakes: Vec<usize> = pancakes[..i_max+1].iter().rev().cloned().collect();
                let mut other_pancakes: Vec<usize> = pancakes[i_max+1..].to_vec();
                flipped_pancakes.append(&mut other_pancakes);
                pancakes = flipped_pancakes.clone();
                steps.append(&mut vec!(flipped_pancakes));
            }
            flips += 1;
        }
    }
    (flips, steps)
}

fn sort_pancakes_desc(num: usize, raw_pancakes: String) -> (usize, Vec<Vec<usize>>) {
    //SPlit pancakes
    let mut pancakes: Vec<usize> = vec!();
    for pancake in raw_pancakes.split(" ") {pancakes.append(&mut vec!(pancake.parse().expect("Error: only enter numbers")));}
    let mut flips: usize = 0;
    let mut steps: Vec<Vec<usize>> = vec!();
    for i in (1..num+1).rev() {
        while match pancakes[..i].iter().min() {Some(min) => min, None => &0} != &pancakes[i-1] {
            if &pancakes[0] == match pancakes[..i].iter().min() {Some(min) => min, None => &0} {
                //Pancake is in beginning, flip
                let mut flipped_pancakes: Vec<usize> = pancakes[..i].iter().rev().cloned().collect();
                let mut other_pancakes: Vec<usize> = pancakes[i..].to_vec();
                flipped_pancakes.append(&mut other_pancakes);
                pancakes = flipped_pancakes.clone();
                steps.append(&mut vec!(flipped_pancakes));
            } else {
                //Bring pancake to beginning
                let i_min = pancakes.iter().enumerate().find(|&r| r.1 == match pancakes[..i].iter().min() {Some(min) => min, None => &0}).unwrap().0;
                let mut flipped_pancakes: Vec<usize> = pancakes[..i_min+1].iter().rev().cloned().collect();
                let mut other_pancakes: Vec<usize> = pancakes[i_min+1..].to_vec();
                flipped_pancakes.append(&mut other_pancakes);
                //println!("p: {:?}, f_p: {:?}", pancakes, flipped_pancakes);
                pancakes = flipped_pancakes.clone();
                steps.append(&mut vec!(flipped_pancakes));
            }
            flips += 1;
        }
    }
    let flipped_pancakes: Vec<usize> = pancakes.iter().rev().cloned().collect();
    steps.append(&mut vec!(flipped_pancakes));
    (flips+1, steps)
}

fn sort_pancakes(num: usize, raw_pancakes: String) -> (usize, String) {
    let asc_sorted_pancakes = sort_pancakes_asc(num.clone(), raw_pancakes.clone());
    let desc_sorted_pancakes = sort_pancakes_desc(num.clone(), raw_pancakes.clone());
    if asc_sorted_pancakes.0 <= desc_sorted_pancakes.0 {
        return (asc_sorted_pancakes.0, format!("{:?}", asc_sorted_pancakes.1));
    }
    (desc_sorted_pancakes.0, format!("{:?}", desc_sorted_pancakes.1))
}