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//! Maps integer intervals to their associated values
use crate::{
interval::{traits::Interval, I64Interval},
set::{
contiguous_integer_set::ContiguousIntegerSet,
ordered_integer_set::OrderedIntegerSet, traits::Intersect,
},
traits::SubsetIndexable,
};
use num::Num;
use std::{collections::BTreeMap, fmt::Debug};
/// Maps `I64Interval`s to values of a numeric type `T`.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct IntegerIntervalMap<T> {
map: BTreeMap<I64Interval, T>,
}
impl<T: Copy + Num> IntegerIntervalMap<T> {
pub fn new() -> Self {
IntegerIntervalMap {
map: BTreeMap::new(),
}
}
/// Adds an integer interval as the `key` with an associated `value`.
/// Any existing intervals intersecting the `key` will be broken up,
/// where the region of intersection will have a value being the sum of
/// the existing value and the new `value`, while the non-intersecting
/// regions will retain their original values.
///
/// # Example
/// ```
/// use math::{
/// interval::I64Interval,
/// partition::integer_interval_map::IntegerIntervalMap,
/// };
///
/// // | value
/// // -1 0 1 2 3 4 | +2
/// // 6 7 8 | +4
/// // 4 5 6 7 | +1
/// //---------------------------
/// // 2 2 2 2 2 3 1 5 5 4 | superposed values
///
/// let mut interval_map = IntegerIntervalMap::new();
/// interval_map.aggregate(I64Interval::new(-1, 4), 2);
/// interval_map.aggregate(I64Interval::new(6, 8), 4);
/// interval_map.aggregate(I64Interval::new(4, 7), 1);
///
/// assert_eq!(interval_map.get(&I64Interval::new(-1, 3)), Some(2));
/// assert_eq!(interval_map.get(&I64Interval::new(4, 4)), Some(3));
/// assert_eq!(interval_map.get(&I64Interval::new(5, 5)), Some(1));
/// assert_eq!(interval_map.get(&I64Interval::new(6, 7)), Some(5));
/// assert_eq!(interval_map.get(&I64Interval::new(8, 8)), Some(4));
/// assert_eq!(interval_map.get(&I64Interval::new(-1, 4)), None);
/// assert_eq!(interval_map.get(&I64Interval::new(6, 8)), None);
/// assert_eq!(interval_map.get(&I64Interval::new(4, 7)), None);
/// ```
pub fn aggregate(&mut self, key: I64Interval, value: T) {
let (start, end) = key.get_start_and_end();
let mut remaining_interval =
OrderedIntegerSet::from_contiguous_integer_sets(vec![key]);
let mut to_add = Vec::new();
let mut to_remove = Vec::new();
// All intervals in the range (start, start)..(end + 1, end + 1)
// intersect with the key due to the lexicographical ordering of
// the ContiguousIntegerSet. Furthermore, there can be at most
// one interval whose start is less than the start of
// the key, and which intersects the key.
for (&interval, &val) in self
.map
.range(
ContiguousIntegerSet::new(start, start)
..ContiguousIntegerSet::new(end + 1, end + 1),
)
.chain(
self.map
.range(..ContiguousIntegerSet::new(start, start))
.rev()
.take(1),
)
{
to_remove.push(interval);
let intersection = interval.intersect(&remaining_interval);
for &common_interval in intersection.get_intervals_by_ref().iter() {
remaining_interval -= common_interval;
to_add.push((common_interval, val + value));
}
for outstanding_interval in
(interval - intersection).into_intervals()
{
to_add.push((outstanding_interval, val));
}
}
for i in remaining_interval
.into_non_empty_intervals()
.into_intervals()
.into_iter()
{
to_add.push((i, value));
}
// remove the old and add the new
for i in to_remove.into_iter() {
self.map.remove(&i);
}
for (k, v) in to_add.into_iter() {
self.map.insert(k, v);
}
}
/// # Example
/// ```
/// use math::{
/// interval::I64Interval,
/// partition::integer_interval_map::IntegerIntervalMap,
/// };
///
/// let mut interval_map = IntegerIntervalMap::new();
/// interval_map.aggregate(I64Interval::new(-1, 4), 2);
/// interval_map.aggregate(I64Interval::new(6, 8), 4);
/// interval_map.aggregate(I64Interval::new(4, 7), 1);
///
/// let expected = vec![
/// (I64Interval::new(-1, 3), 2),
/// (I64Interval::new(4, 4), 3),
/// (I64Interval::new(5, 5), 1),
/// (I64Interval::new(6, 7), 5),
/// (I64Interval::new(8, 8), 4),
/// ];
/// assert_eq!(interval_map.len(), 5);
/// for ((interval, val), (expected_interval, exptected_val)) in
/// interval_map.iter().zip(expected.iter())
/// {
/// assert_eq!(interval, expected_interval);
/// assert_eq!(val, exptected_val);
/// }
/// ```
pub fn iter(&self) -> std::collections::btree_map::Iter<I64Interval, T> {
self.map.iter()
}
/// Returns the number of common refinements resulted from aggregating the
/// intervals
///
/// # Example
/// ```
/// use math::{
/// interval::I64Interval,
/// partition::integer_interval_map::IntegerIntervalMap,
/// };
///
/// let mut interval_map = IntegerIntervalMap::new();
/// interval_map.aggregate(I64Interval::new(2, 6), 2.);
/// interval_map.aggregate(I64Interval::new(4, 8), 2.);
/// interval_map.aggregate(I64Interval::new(8, 9), 3.);
///
/// // the common refinements are now [2, 3], [4, 6], [7, 7], [8, 8], [9, 9]
/// assert_eq!(interval_map.len(), 5);
///
/// let expected = vec![
/// (I64Interval::new(2, 3), 2.),
/// (I64Interval::new(4, 6), 4.),
/// (I64Interval::new(7, 7), 2.),
/// (I64Interval::new(8, 8), 5.),
/// (I64Interval::new(9, 9), 3.),
/// ];
///
/// for ((interval, val), (expected_interval, exptected_val)) in
/// interval_map.iter().zip(expected.iter())
/// {
/// assert_eq!(interval, expected_interval);
/// assert_eq!(val, exptected_val);
/// }
/// ```
pub fn len(&self) -> usize {
self.map.len()
}
/// Converts into the underlying `BTreeMap`
pub fn into_map(self) -> BTreeMap<I64Interval, T> {
self.map
}
/// Returns a `Some` value only if the key corresponds to one of the current
/// exact intervals and not its subset or superset.
///
/// # Example
/// ```
/// use math::{
/// interval::I64Interval,
/// partition::integer_interval_map::IntegerIntervalMap,
/// };
///
/// let mut interval_map = IntegerIntervalMap::new();
/// interval_map.aggregate(I64Interval::new(2, 5), 1);
/// assert_eq!(interval_map.get(&I64Interval::new(2, 5)), Some(1));
/// assert_eq!(interval_map.get(&I64Interval::new(2, 4)), None);
/// assert_eq!(interval_map.get(&I64Interval::new(2, 6)), None);
/// ```
pub fn get(&self, key: &I64Interval) -> Option<T> {
self.map.get(key).map(|&k| k)
}
}
impl<T: Copy + Num + Debug> Default for IntegerIntervalMap<T> {
fn default() -> Self {
Self::new()
}
}
impl<T> IntoIterator for IntegerIntervalMap<T> {
type IntoIter = <BTreeMap<I64Interval, T> as IntoIterator>::IntoIter;
type Item = <BTreeMap<I64Interval, T> as IntoIterator>::Item;
fn into_iter(self) -> Self::IntoIter {
self.map.into_iter()
}
}
impl<T> SubsetIndexable<I64Interval, I64Interval> for IntegerIntervalMap<T> {
fn get_set_containing(&self, subset: &I64Interval) -> Option<I64Interval> {
let start = subset.get_start();
// the containing interval must be < (start + 1, start + 1)
// lexicographically
for (interval, _) in self
.map
.range(..I64Interval::new(start + 1, start + 1))
.rev()
{
if subset.is_subset_of(interval) {
return Some(*interval);
}
if interval.get_end() < start {
return None;
}
}
None
}
}
#[cfg(test)]
mod tests {
use crate::{
interval::I64Interval, iter::CommonRefinementZip,
partition::integer_interval_map::IntegerIntervalMap,
};
#[test]
fn test_common_refinement_zip_integer_interval_map() {
let mut map1 = IntegerIntervalMap::new();
map1.aggregate(I64Interval::new(1, 5), 1);
let mut map2 = IntegerIntervalMap::new();
map2.aggregate(I64Interval::new(3, 6), 2);
let refined: Vec<(I64Interval, Vec<Option<i32>>)> =
map1.iter().common_refinement_zip(map2.iter()).collect();
let expected = vec![
(I64Interval::new(1, 2), vec![Some(1), None]),
(I64Interval::new(3, 5), vec![Some(1), Some(2)]),
(I64Interval::new(6, 6), vec![None, Some(2)]),
];
assert_eq!(refined, expected);
}
}