Anonymous user
Mind boggling card trick: Difference between revisions
Added Rust.
m (corrected a misspelling, added whitespace for the last task's requirement, added whitespace before the TOC (table of contents), added punctuation to 1st two main bullets points to be consistent, as the last two have 'em.) |
(Added Rust.) |
||
Line 252:
Correctness of the mathematician's assertion: 100% (out of 500 trials).
</pre>
=={{header|Rust}}==
{{libheader|rand}}
<lang rust>extern crate rand; // 0.5.5
use rand::Rng;
use std::iter::repeat;
#[derive(Debug, Eq, PartialEq, Clone)]
enum Colour {
Black,
Red,
}
use Colour::*;
fn main() {
let mut rng = rand::thread_rng();
//Create our deck.
let mut deck: Vec<_> = repeat(Black).take(26)
.chain(repeat(Red).take(26))
.collect();
rng.shuffle(&mut deck);
let mut black_stack = vec![];
let mut red_stack = vec![];
let mut discarded = vec![];
//Deal our cards.
print!("Discarding:");
while let (Some(card), Some(next)) = (deck.pop(), deck.pop()) {
print!(" {}", if card == Black { "B" } else { "R" });
match card {
Red => red_stack.push(next),
Black => black_stack.push(next),
}
discarded.push(card);
}
println!();
// Choose how many to swap.
let max = red_stack.len().min(black_stack.len());
let num = rng.gen_range(1, max);
println!("Exchanging {} cards", num);
// Actually swap our cards.
for _ in 0..num {
let red = rng.choose_mut(&mut red_stack).unwrap();
let black = rng.choose_mut(&mut black_stack).unwrap();
std::mem::swap(red, black);
}
//Count how many are red and black.
let num_black = black_stack.iter()
.filter(|&c| c == &Black)
.count();
let num_red = red_stack.iter()
.filter(|&c| c == &Red)
.count();
println!("Number of black cards in black stack: {}", num_black);
println!("Number of red cards in red stack: {}", num_red);
}</lang>
{{out}}
<pre>Discarding: R R B B R R B R R B B B B B R R R B B B R R R B R R
Exchanging 5 cards
Number of black cards in black stack: 4
Number of red cards in red stack: 4</pre>
=={{header|zkl}}==
| |||