chapter_8_exercises.rs

use std::collections::HashMap;

// Given a list of integers, use a vector and return the mean (the average value)
pub fn vec_mean(vec: &Vec<i32>) -> f64 {
    let sum = vec_sum(&vec);

    sum as f64 / vec.len() as f64
}

// Given a list of integers, use a vector and return the median (when sorted, the value in the middle position)
pub fn vec_median(sorted_vec: &Vec<i32>) -> f64 {
    if sorted_vec.len() == 0 {
        return 0.0
    }

    let middle_position = sorted_vec.len() / 2;

    if sorted_vec.len() % 2 == 0 {
        let middle_upper_position = sorted_vec[middle_position];
        let middle_lower_position = sorted_vec[middle_position - 1];
        return (middle_lower_position as f64 + middle_upper_position as f64) / 2.0
    }


    sorted_vec[middle_position] as f64

}

// Given a list of integers, return the mode (the value that occurs most often; a hash map will be helpful here) of the list.
pub fn vec_mode(vec: &Vec<i32>) -> i32 {
    let mut occurrences: HashMap<i32, i32> = HashMap::with_capacity(vec.len());

    let mut current_max_value = i32::min_value();
    let mut current_max_occurrences = 0;

    for current_value in vec {
        let current_value_occurrences = occurrences.entry(current_value.clone()).or_insert(0);
        *current_value_occurrences += 1;

        if current_value_occurrences > &mut current_max_occurrences {
            current_max_occurrences = current_value_occurrences.clone();
            current_max_value = current_value.clone();
        }
    }

    current_max_value
}

fn vec_sum(vec: &Vec<i32>) -> i32 {
    let mut sum = 0;

    for i in vec {
        sum += i;
    }

    sum
}


pub fn pig_latin(text: &str) -> String {
    let mut result = String::new();

    let mut add_space = false;
    for word in text.split_whitespace() {

        if add_space {
            result.push(' ');
        }

        let mut word_chars = word.chars();

        if let Some(first_chr) = word_chars.next() {
            if first_chr == 'a' || first_chr == 'e' || first_chr == 'i' || first_chr == 'o' || first_chr == 'u' || first_chr == 'A' || first_chr == 'E' || first_chr == 'I' || first_chr == 'O' || first_chr == 'U' {
                result.push_str(&format!("{}-hay", word))
            }
            else {
                result.push_str(&format!("{}-{}ay", word_chars.as_str(), first_chr))
            }
        }

        add_space = true;
    }

    result
}