使用 rust lang 的斐波那契序列

Question

我想使用 Rust 创建斐波那契数列列表 我写了这段代码，但我认为有更干净和简短的方法来做到这一点 ...................................................... ................................................

fn main() {
    let mut first_num: i128 = 0;
    let mut second_num:i128 = 1;
    let mut resulte: i128;

    let mut list = Vec::with_capacity(200);
    while list.len() < 100 {
        resulte = first_num + second_num;
        list.push(resulte);
        println!("The Fib Number is: {}", resulte);
       
        second_num = first_num;
        first_num = resulte;
    }
}

Answer 1

非递归函数。

n

用于计算序列成员的排名。

pub fn fibonacci(n: i32) -> u64 {
    if n < 0 {
        panic!("{} is negative!", n);
    } else if n == 0 {
        panic!("zero is not a right argument to fibonacci()!");
    } else if n == 1 {
        return 1;
    }

    let mut sum = 0;
    let mut last = 0;
    let mut curr = 1;
    for _i in 1..n {
        sum = last + curr;
        last = curr;
        curr = sum;
    }
    sum
}

递归函数。

这段代码展示了计算斐波那契数列的递归方法，复杂度是指数级的。

n

用于计算序列成员的排名。

pub fn fibonacci_reccursive(n: i32) -> u64 {
    if n < 0 {
        panic!("{} is negative!", n);
    }
    match n {
        0 => panic!("zero is not a right argument to fibonacci_reccursive()!"),
        1 | 2 => 1,
        3 => 2,
        /*
        50    => 12586269025,
        */
        _ => fibonacci_reccursive(n - 1) + fibonacci_reccursive(n - 2),
    }
}