Problem:
Score : 300 points

Problem Statement

You are given three integers A, B and C. Find the minimum number of operations required to make A, B and C all equal by repeatedly performing the following two kinds of operations in any order:

Choose two among A, B and C, then increase both by 1.

Choose one among A, B and C, then increase it by 2.

It can be proved that we can always make A, B and C all equal by repeatedly performing these operations.

Constraints

0 \leq A,B,C \leq 50

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the minimum number of operations required to make A, B and C all equal.

Sample Input 1

2 5 4

Sample Output 1

2

We can make A, B and C all equal by the following operations:

Increase A and C by 1. Now, A, B, C are 3, 5, 5, respectively.

Increase A by 2. Now, A, B, C are 5, 5, 5, respectively.

Sample Input 2

2 6 3

Sample Output 2

5

Sample Input 3

31 41 5

Sample Output 3

23

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io::*;
use std::cmp;

fn read<T: std::str::FromStr>() -> T {
    let stdin = stdin();
    let mut buf = String::new();
	stdin.lock().read_line(&mut buf);
	buf.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
	read::<String>().trim().split_whitespace()
        .map(|w| w.parse().ok().unwrap()).collect()
}

fn main() {
    let v = read_vec::<usize>();
    let (a,b,c) = (v[0],v[1],v[2]);
    let ea = a % 2;
    let eb = b % 2;
    let ec = c % 2;
    let s = ea + eb + ec;
    let max = cmp::max(cmp::max(a,b),c);
    let ds = 3 * max - a - b - c;
    let ans: usize;
    if s == 0 || s == 3 {
        ans = ds / 2;
    } else if s == 1 {
        if max%2 == 1 {
            ans = ds / 2;
        } else {
            ans = (ds + 3) / 2;
        }
    } else {
        if max%2 == 0 {
            ans = ds / 2;
        } else {
            ans = (ds + 3) / 2;
        }
    }
    println!("{}",ans);
}