find the variance of all nodes in a linked list in rust

To find the variance of all nodes in a linked list in Rust, we need to first compute the mean and then iterate through the linked list to calculate the variance. Here's a sample implementation:

main.rs
use std::collections::LinkedList;

fn main() {
    let mut list = LinkedList::new();

    // Populate the linked list
    list.push_back(1.0);
    list.push_back(2.0);
    list.push_back(3.0);
    list.push_back(4.0);
    list.push_back(5.0);

    let mean = list.iter().sum::<f64>() / list.len() as f64;

    let variance = list
        .iter()
        .map(|x| (x - mean).powi(2))
        .sum::<f64>()
        / (list.len() as f64 - 1.0); // Use unbiased estimator

    println!("The variance of all nodes in the linked list is: {}", variance);
}
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Here, we first create a linked list using the LinkedList data structure from the std::collections module. We then populate the list with some example values.

Next, we compute the mean of the list using the iter() method and the sum() method from the Iterator trait. We divide the sum by the length of the list to get the mean.

Finally, we calculate the variance by iterating through the list again using the iter() method and the map() method to compute the squared difference from the mean for each value, and then we sum up the results. We divide the sum by (n-1) where n is the length of the list to get the unbiased estimator for variance.