63 lines
997 B
Rust
63 lines
997 B
Rust
use std::{
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fs::File,
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io::{Read, Write},
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os::unix::io::FromRawFd,
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};
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fn fib(n: u64) -> u64 {
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let mut y = 0;
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let mut y1 = 1;
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let mut y2 = 0;
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for _ in 0..n {
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y = y1 + y2;
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y2 = y1;
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y1 = y;
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}
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y
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}
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fn main() {
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nested::magic_header();
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eprintln!(" Fibonacci Sequence");
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nested::magic_header();
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eprintln!(
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"
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interface (Sequence ℕ) 0 1"
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);
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let mut f0 = unsafe { File::from_raw_fd(0) };
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eprintln!(
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"
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>0: n
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( ℕ )
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( MachineInt )
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( MachineWord )
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( Stream MachineSyllab )
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"
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);
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let mut f1 = unsafe { File::from_raw_fd(1) };
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eprintln!(
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"
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<1: n'th fibonacci number
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( ℕ )
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( MachineInt )
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( MachineWord )
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( Stream MachineSyllab )
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"
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);
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nested::magic_header();
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let mut bytes = [0 as u8; 8];
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f0.read_exact(&mut bytes).expect("");
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let n = u64::from_le_bytes(bytes);
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bytes = fib(n).to_le_bytes();
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f1.write(&bytes).expect("");
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}
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