37 lines
1.1 KiB
Rust
37 lines
1.1 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::os;
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fn ack(m: int, n: int) -> int {
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if m == 0 {
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return n + 1
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} else {
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if n == 0 {
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return ack(m - 1, 1);
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} else {
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return ack(m - 1, ack(m, n - 1));
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}
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}
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}
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fn main() {
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let args = os::args();
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let args = if os::getenv("RUST_BENCH").is_some() {
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vec!("".to_string(), "12".to_string())
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} else if args.len() <= 1u {
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vec!("".to_string(), "8".to_string())
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} else {
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args.move_iter().collect()
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};
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let n = from_str::<int>(args.get(1).as_slice()).unwrap();
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println!("Ack(3,{}): {}\n", n, ack(3, n));
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}
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