find the standard deviation of all nodes in a linked list in rust

main.rs
use std::f64;

// Define a struct for the linked list node
struct Node {
    data: f64,
    next: Option<Box<Node>>,
}

// Calculate the standard deviation of all nodes in a linked list
fn std_dev_of_list(head: Option<Box<Node>>) -> f64 {
    let mut lst = Vec::new();

    // Traverse through the linked list and collect all the data points into a vector
    let mut curr_node = head;
    while let Some(node) = curr_node {
        lst.push(node.data);
        curr_node = node.next;
    }

    // Calculate the mean of the vector
    let mean = lst.iter().sum::<f64>() / lst.len() as f64;

    // Calculate the variance of the vector
    let variance = lst.iter()
                      .map(|val| (val - mean).powi(2))
                      .sum::<f64>() / lst.len() as f64;

    // Calculate the standard deviation from the variance
    variance.sqrt()
}

// Example usage
fn main() {
    let n1 = Node { data: 1.0, next: None };
    let n2 = Node { data: 2.0, next: Some(Box::new(n1)) };
    let n3 = Node { data: 3.0, next: Some(Box::new(n2)) };
    let head = Some(Box::new(n3));

    let std_dev = std_dev_of_list(head);
    println!("Standard deviation of all nodes in a linked list is {}", std_dev);
}
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