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shawakash/compile_time.rs

Created February 26, 2025 20:10
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  1. shawakash created this gist Feb 26, 2025.
    62 changes: 62 additions & 0 deletions compile_time.rs
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,62 @@
    use num_bigint::BigUint;
    use num_traits::{One, Zero};

    const FIB_LEN: usize = 1000;

    const FIBS: [u128; FIB_LEN] = create_fib_array();

    const fn create_fib_array() -> [u128; FIB_LEN] {
    let mut arr = [0u128; FIB_LEN];
    let mut i = 0;
    while i < FIB_LEN {
    arr[i] = match i {
    0 => 0,
    1 => 1,
    n => {
    let mut f1: u128 = 0;
    let mut f2: u128 = 1;
    let mut j = 2;
    while j <= n {
    let f3 = f1.wrapping_add(f2);
    f1 = f2;
    f2 = f3;
    j += 1;
    }
    f2
    }
    };
    i += 1;
    }
    arr
    }

    fn fib(num: u128) -> BigUint {
    if num == 0 {
    return BigUint::zero();
    }
    if num == 1 {
    return BigUint::one();
    }

    let mut f1 = BigUint::zero();
    let mut f2 = BigUint::one();

    for _ in 2..num {
    let f3 = &f1 + &f2;
    f1 = f2;
    f2 = f3;
    }

    return f2;
    }

    fn main() {
    println!("First 10 Fibonacci numbers:");
    for (i, &fib) in FIBS.iter().enumerate() {
    println!("Fib({}) = {}", i, fib);
    }

    println!("\nSome larger Fibonacci numbers (runtime):");
    println!("Fib(100) = {}", fib(5000));
    println!("Fib(1000) = {}", fib(1000));
    }