1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
use std::ops::{Deref, DerefMut};
use std::collections::VecDeque;
use std::collections::vec_deque;

#[derive(Debug, Clone, Hash)]
pub struct Node<T> {
    value: T,
    children: VecDeque<Node<T>>,
}

impl<T> Node<T> {
    pub fn new(value: T) -> Node<T> {
        Node {
            value: value,
            children: VecDeque::new(),
        }
    }

    pub fn len(&self) -> usize {
        self.children.len()
    }

    pub fn push_back(&mut self, value: Node<T>) {
        self.children.push_back(value);
    }

    pub fn push_front(&mut self, value: Node<T>) {
        self.children.push_front(value);
    }

    pub fn insert(&mut self, index: usize, value: Node<T>) {
        self.children.insert(index, value);
    }

    pub fn pop_front(&mut self) -> Option<Node<T>> {
        self.children.pop_front()
    }

    pub fn pop_back(&mut self) -> Option<Node<T>> {
        self.children.pop_back()
    }

    pub fn remove(&mut self, index: usize) -> Option<Node<T>> {
        self.children.remove(index)
    }

    pub fn get(&self, index: usize) -> Option<&Node<T>> {
        self.children.get(index)
    }

    pub fn get_mut(&mut self, index: usize) -> Option<&mut Node<T>> {
        self.children.get_mut(index)
    }

    pub fn front(&self) -> Option<&Node<T>> {
        self.children.front()
    }

    pub fn front_mut(&mut self) -> Option<&mut Node<T>> {
        self.children.front_mut()
    }

    pub fn back(&self) -> Option<&Node<T>> {
        self.children.back()
    }

    pub fn back_mut(&mut self) -> Option<&mut Node<T>> {
        self.children.back_mut()
    }

    pub fn children(&self) -> vec_deque::Iter<Node<T>> {
        self.children.iter()
    }

    pub fn children_mut(&mut self) -> vec_deque::IterMut<Node<T>> {
        self.children.iter_mut()
    }

    /// Pre-order traversal with the given function.
    pub fn traverse<F>(&self, f: F)
        where F: Fn(&Node<T>)
    {
        f(self);
        for child in self.children() {
            child.traverse(&f)
        }
    }

    /// Post-order traversal with the given function.
    pub fn traverse_mut<F>(&mut self, mut f: F)
        where F: FnMut(&mut Node<T>)
    {
        f(self);
        for child in self.children_mut() {
            child.traverse_mut(&mut f)
        }
    }
}

impl<T> Deref for Node<T> {
    type Target = T;

    fn deref(&self) -> &T {
        &self.value
    }
}

impl<T> DerefMut for Node<T> {
    fn deref_mut(&mut self) -> &mut T {
        &mut self.value
    }
}