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
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129

extern crate num;

use self::num::traits::{Num};
use self::num::traits::{One};
use common::{mid};

pub struct SegmentPointTree<N, S>{
    root: Node<N, S>,
    lower_bound: N, 
    upper_bound: N, 
    default: S,
    combine: Box<F<S>>
}

#[derive(PartialEq, Eq, Debug)]
struct Node<N, S> {
    start: N,
    end: N,
    value: S, 
    left: Option<Box<Node<N, S>>>,
    right: Option<Box<Node<N, S>>>,
}

pub type F<S> = Fn(&S, &S) -> S;

impl<N: Num+Clone+Ord, S: Clone> SegmentPointTree<N, S> {
    pub fn new(lower_bound: N, upper_bound: N, default_value: S,
               combine: Box<F<S>>) -> Self 
    {
        if upper_bound < lower_bound {
            panic!("Invalid bounds (lower_bound must not be greater than upper_bound)");
        }
        SegmentPointTree {
            lower_bound: lower_bound.clone(),
            upper_bound: upper_bound.clone(),
            default: default_value.clone(),
            root: Node::new(lower_bound, upper_bound, &default_value),
            combine: combine
        }
    }

    pub fn query(&self, point: N) -> Option<S> {
        let s = self.default.clone();
        if point > self.upper_bound || point < self.lower_bound {
            None
        } else {
            Some(self.root.query(point, &*self.combine, s))
        }
    }

    pub fn bounds(&self) -> (N, N) {
        return (self.lower_bound.clone(), self.upper_bound.clone())
    }

    pub fn insert(&mut self, start: N, end: N, segment: S) -> () {
        if start < self.lower_bound || end > self.upper_bound {
            panic!("Can't insert outside of bounds");
        }
        self.root.insert(start, end, &segment, &self.default, &*self.combine);
    }
}

impl<N: Num+Clone+Ord, S: Clone> Node<N, S> {
    fn new(start: N, end: N, default_value: &S) -> Self {
        Node {
            value: default_value.clone(),
            start: start,
            end: end,
            left: None,
            right: None,
        }
    }

    fn new_son(start: N, end: N, default_value: &S) -> Option<Box<Self>> {
        Some(Box::new(Node::new(start, end, &default_value)))
    }

    fn query(&self, point: N, combine: &F<S>, acc: S) -> S { 
        let acc2 = combine(&acc, &self.value);
        let mid_n = mid(self.start.clone(), self.end.clone());
        let ref son = if point <= mid_n {
            &self.left
        } else {
            &self.right
        };
        match son.as_ref() {
            None => acc2,   
            Some(n) => n.query(point, combine, acc2)
        }// .map_or(acc2, |n| n.query(point, combine, acc2))
    }

    fn insert(&mut self, start_s: N, end_s: N, value_s: &S, 
              default: &S, combine: &F<S>) -> () {
        if start_s == self.start && end_s == self.end {
            // ugh.
            self.value = combine(&self.value, value_s);
            return;
        }
        let mid_n = mid(self.start.clone(), self.end.clone());
        if end_s <= mid_n {
            // only left
            if self.left.is_none() {
                self.left = Node::new_son(self.start.clone(), mid_n, default);
            }
            self.left.as_mut().map(|n| n.insert(start_s, end_s, 
                                                value_s, default, combine));
        } else if start_s > mid_n {
            // only right
            if self.right.is_none() {
                self.right = Node::new_son(mid_n + One::one(), self.end.clone(), default);
            }
            self.right.as_mut().map(|n| n.insert(start_s, end_s, 
                                                 value_s, default, combine));
        } else {
            // both
            if self.left.is_none() {
                self.left = Node::new_son(self.start.clone(), mid_n.clone(), default);
            }
            self.left.as_mut().map(|n| n.insert(start_s, mid_n.clone(), 
                                                value_s, default, combine));
            if self.right.is_none() {
                self.right = Node::new_son(mid_n.clone() + One::one(), self.end.clone(), default);
            }
            self.right.as_mut().map(|n| n.insert(mid_n + One::one(), end_s, 
                                                 value_s, default, combine));
        }
    }
}