source code
// The Computer Language Benchmarks Game
// http://benchmarksgame.alioth.debian.org/
//
// contributed by the Rust Project Developers
// contributed by TeXitoi
// *reset*
extern crate typed_arena;
use std::thread;
use typed_arena::Arena;
struct Tree<'a> {
l: Option<&'a Tree<'a>>,
r: Option<&'a Tree<'a>>,
}
fn item_check(t: &Option<&Tree>) -> i32 {
match *t {
None => 0,
Some(&Tree { ref l, ref r }) => 1 + item_check(l) + item_check(r)
}
}
fn bottom_up_tree<'r>(arena: &'r Arena<Tree<'r>>, depth: i32)
-> Option<&'r Tree<'r>> {
if depth >= 0 {
let t: &Tree<'r> = arena.alloc(Tree {
l: bottom_up_tree(arena, depth - 1),
r: bottom_up_tree(arena, depth - 1)
});
Some(t)
} else {
None
}
}
fn inner(depth: i32, iterations: i32) -> String {
let mut chk = 0;
for i in 1 .. iterations + 1 {
let arena = Arena::new();
let a = bottom_up_tree(&arena, depth);
chk += item_check(&a);
}
format!("{}\t trees of depth {}\t check: {}",
iterations, depth, chk)
}
fn main() {
let n = std::env::args_os().nth(1)
.and_then(|s| s.into_string().ok())
.and_then(|n| n.parse().ok())
.unwrap_or(10);
let min_depth = 4;
let max_depth = if min_depth + 2 > n {min_depth + 2} else {n};
{
let arena = Arena::new();
let depth = max_depth + 1;
let tree = bottom_up_tree(&arena, depth);
println!("stretch tree of depth {}\t check: {}",
depth, item_check(&tree));
}
let long_lived_arena = Arena::new();
let long_lived_tree = bottom_up_tree(&long_lived_arena, max_depth);
let messages = (min_depth..max_depth + 1).filter(|&d| d % 2 == 0).map(|depth| {
let iterations = 1 << ((max_depth - depth + min_depth) as u32);
thread::spawn(move || inner(depth, iterations))
}).collect::<Vec<_>>();
for message in messages.into_iter() {
println!("{}", message.join().unwrap());
}
println!("long lived tree of depth {}\t check: {}",
max_depth, item_check(&long_lived_tree));
}