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
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171

extern crate num;

use std::hash::Hash;
use std::collections::BTreeSet;
use std::collections::HashSet;
use std::collections::VecDeque;
// use std::cmp;

struct Node< T, V > where T : Ord + Default + Clone, V: Clone + Hash + Eq {
    _index: isize,
    _parent: isize,
    _child_left: isize,
    _child_right: isize,
    _segs: Vec< V >,
    _bound_l: T, //todo: use generic types?
    _bound_r: T,
}


impl < T, V > Default for Node< T, V > where T: Ord + Default + Clone, V: Clone + Hash + Eq {
    fn default() -> Node < T, V > {
        Node {
            _index: -1isize,
            _parent: -1isize,
            _child_left: -1isize,
            _child_right: -1isize,
            _segs: vec![],
            _bound_l: Default::default(),
            _bound_r: Default::default(),
        }
    }
}

pub struct TreeSeg < T, V > where T : Ord + Default + Clone, V: Clone + Hash + Eq {
    _intervals: Vec< Node< T, V > >,
    _root_index: isize,
}

impl < T, V > TreeSeg< T, V > where T: Ord + Default + Clone, V: Clone + Hash + Eq {
    ///builds a tree using input segments
    pub fn init( input: &[( T, T, V )] ) -> TreeSeg< T, V > {
        let mut intervals = BTreeSet::new();
        for i in input {
            intervals.insert( i.0.clone() );
            intervals.insert( i.1.clone() );
        }
        let mut buf = vec![];
        let mut queue = VecDeque::new();
        
        for i in &intervals {
            let n_index = buf.len();
            let n = Node {
                _index: n_index as isize,
                _bound_l: (*i).clone(),
                _bound_r: (*i).clone(),
                ..Default::default()
            };
            // println!( "elementary intervals created: [{},{}]", n._bound_l, n._bound_r );
            buf.push( n );
            queue.push_back(n_index);
        }
        while queue.len() > 1usize {
            let drained : Vec<usize> = queue.drain(..).collect();
            let num_parents = drained.len() / 2 + drained.len() % 2;
            for i in 0..num_parents {
                let n_index = buf.len();
                if (i == num_parents-1) && ((drained.len() % 2) == 1) {
                    //odd one left, combine it with the last created node
                    let nr = i*2;
                    // println!("left: {}", (buf.len()-1) );
                    // println!("right: {}", drained[nr] );
                    let n = Node {
                        _index: n_index as isize,
                        _child_left: (buf.len()-1) as isize,
                        _child_right: drained[nr] as isize,
                        // _num_children: buf[buf.len()-1]._num_children + buf[drained[nr]]._num_children + 2,
                        // _height: cmp::max( buf[buf.len()-1]._height, buf[drained[nr]]._height ) + 1,
                        _bound_l: buf[buf.len()-1]._bound_l.clone(),
                        _bound_r: buf[drained[nr]]._bound_r.clone(),
                        ..Default::default()
                    };
                    // println!( "bound created: [{},{}]", n._bound_l, n._bound_r );
                    queue.pop_back(); //discard the previously queued parent index
                    buf.push( n );
                } else {   
                    let nl = i*2;
                    let nr = i*2+1;
                    // println!("left: {}", drained[nl] );
                    // println!("right: {}", drained[nr] );
                    buf[drained[nl]]._parent = n_index as isize;
                    buf[drained[nr]]._parent = n_index as isize;
                    let n = Node {
                        _index: n_index as isize,
                        _child_left: drained[nl] as isize,
                        _child_right: drained[nr] as isize,
                        // _num_children: buf[drained[nl]]._num_children + buf[drained[nr]]._num_children + 2,
                        // _height: cmp::max( buf[drained[nl]]._height, buf[drained[nr]]._height ) + 1,
                        _bound_l: buf[drained[nl]]._bound_l.clone(),
                        _bound_r: buf[drained[nr]]._bound_r.clone(),
                        ..Default::default()
                    };
                    // println!( "bound created: [{},{}]", n._bound_l, n._bound_r );
                    buf.push( n );
                }
                queue.push_back( n_index ); //queue the parent index
            }
        }
        
        let buf_size = buf.len();
        let mut t = TreeSeg {
            _intervals: buf,
            _root_index: if buf_size > 0 { (buf_size-1) as isize } else { -1isize },
        };
        
        //insert segments into the tree
        for i in input {
            let mut q = vec![];
            q.push( t._root_index );
            let left = i.0.clone();
            let right = i.1.clone();
            let id = i.2.clone();
            while q.len() > 0 {
                let index = q.pop().unwrap();
                if index != -1 {
                    let n = index as usize;
                    if left <= t._intervals[n]._bound_l && right >= t._intervals[n]._bound_r {
                        t._intervals[n]._segs.push( id.clone() );
                    } else if left > t._intervals[n]._bound_r || right < t._intervals[n]._bound_l {
                        //do nothing
                    } else {
                        q.push( t._intervals[n]._child_left );
                        q.push( t._intervals[n]._child_right );
                    }
                }
            }
        }
        
        t
    }
    ///get total number of nodes in tree
    pub fn len_nodes( & self ) -> usize {
        self._intervals.len()
    }
    ///get a list of segments that is contained in the bound
    pub fn get_segs_from_bound( & self, bound: ( T, T) ) -> Vec< V > {
        let l = bound.0;
        let r = bound.1;
        let mut hs = HashSet::new();
        let mut q = vec![];
        if self._root_index >= 0 {
            q.push( self._root_index );
            while q.len() > 0 {
                let index = q.pop().unwrap();
                if index != -1 {
                    let n = index as usize;
                    if l > self._intervals[n]._bound_r || r < self._intervals[n]._bound_l {
                        //nothing
                    } else {
                        for i in &self._intervals[n]._segs {
                            hs.insert( i );
                        }
                        q.push( self._intervals[n]._child_left );
                        q.push( self._intervals[n]._child_right );
                    }
                }
            }
        }
        let ret = hs.drain().cloned().collect();
        ret
    }
}