87 lines
No EOL
3.2 KiB
C++
87 lines
No EOL
3.2 KiB
C++
//
|
|
// Created by maximilian on 16.04.22.
|
|
//
|
|
#include <cassert>
|
|
#include <bit>
|
|
#include <stack>
|
|
#include "segment_tree.h"
|
|
|
|
SegmentTree::SegmentTree(const std::vector<RectCoord> &coords):
|
|
_num_leaf_nodes(coords.size() -1),
|
|
// reserve nodes for a full binary tree with at least as many leaves as intervals
|
|
_num_meta_nodes(std::bit_ceil(_num_leaf_nodes) -1),
|
|
_nodes(2 * _num_meta_nodes + 1, {0, coords[_num_leaf_nodes].coord, coords[_num_leaf_nodes].coord, 0}) {
|
|
|
|
assert(!coords.empty());
|
|
|
|
// Initialize all nodes with zero coverage and dummy interval
|
|
|
|
// We initialize the tree from bottom up, keeping track of the index ranges
|
|
// and the length of the corresponding segment
|
|
|
|
for(Index leaf_node_idx = 0 ; leaf_node_idx < _num_leaf_nodes ; ++leaf_node_idx) {
|
|
_nodes[leaf_node_idx + _num_meta_nodes].left_coord = coords[leaf_node_idx].coord;
|
|
_nodes[leaf_node_idx + _num_meta_nodes].right_coord = coords[leaf_node_idx + 1].coord;
|
|
}
|
|
// Note that there are remaining leafs that represent dummy ranges
|
|
for(Index node_idx = _num_meta_nodes - 1; node_idx != -1 ; --node_idx) {
|
|
_nodes[node_idx].left_coord = left_child(node_idx).left_coord;
|
|
_nodes[node_idx].right_coord = right_child(node_idx).right_coord;
|
|
}
|
|
|
|
assert(_nodes.front().left_coord == coords.front().coord);
|
|
assert(_nodes.front().right_coord == coords.back().coord);
|
|
assert(_nodes.front().segment_length() == coords.back().coord - coords.front().coord);
|
|
}
|
|
|
|
void SegmentTree::add_interval(Interval interval) {
|
|
std::stack<Index> visit_to;
|
|
std::vector<Index> update_to;
|
|
visit_to.push(0);
|
|
while(!visit_to.empty()) {
|
|
Index node_idx = visit_to.top();
|
|
visit_to.pop();
|
|
if (interval.left <= _nodes[node_idx].left_coord && _nodes[node_idx].right_coord <= interval.right) {
|
|
add_coverage(node_idx);
|
|
} else {
|
|
if(interval.left < left_child(node_idx).right_coord) {
|
|
visit_to.push(left_child_idx(node_idx));
|
|
}
|
|
if(right_child(node_idx).left_coord < interval.right) {
|
|
visit_to.push(right_child_idx(node_idx));
|
|
}
|
|
if(!_nodes[node_idx].covered()) {
|
|
update_to.push_back(node_idx);
|
|
}
|
|
}
|
|
}
|
|
for(auto update_idx : update_to) {
|
|
update_covered_length(update_idx);
|
|
}
|
|
}
|
|
|
|
void SegmentTree::remove_interval(Interval interval) {
|
|
std::stack<Index> visit_to;
|
|
std::vector<Index> update_to;
|
|
visit_to.push(0);
|
|
while(!visit_to.empty()) {
|
|
Index node_idx = visit_to.top();
|
|
visit_to.pop();
|
|
if (interval.left <= _nodes[node_idx].left_coord && _nodes[node_idx].right_coord <= interval.right) {
|
|
remove_coverage(node_idx);
|
|
} else {
|
|
if(interval.left < left_child(node_idx).right_coord) {
|
|
visit_to.push(left_child_idx(node_idx));
|
|
}
|
|
if(right_child(node_idx).left_coord < interval.right) {
|
|
visit_to.push(right_child_idx(node_idx));
|
|
}
|
|
if(!_nodes[node_idx].covered()) {
|
|
update_to.push_back(node_idx);
|
|
}
|
|
}
|
|
}
|
|
for(auto update_idx : update_to) {
|
|
update_covered_length(update_idx);
|
|
}
|
|
} |