mirror of
https://github.com/meilisearch/MeiliSearch
synced 2025-07-04 04:17:10 +02:00
Reintroduce the distinct search system
This commit is contained in:
Clément Renault
parent
74fa9ee4df
commit
96139da0d2
6 changed files with 275 additions and 565 deletions
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@ -1,13 +1,8 @@
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mod dfa;
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mod query_enhancer;
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use meilisearch_tokenizer::is_cjk;
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pub use self::dfa::{build_dfa, build_prefix_dfa, build_exact_dfa};
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pub use self::query_enhancer::QueryEnhancer;
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pub use self::query_enhancer::QueryEnhancerBuilder;
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pub const NGRAMS: usize = 3;
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pub fn normalize_str(string: &str) -> String {
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let mut string = string.to_lowercase();
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@ -1,437 +0,0 @@
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use std::cmp::Ordering::{Equal, Greater, Less};
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use std::ops::Range;
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/// Return `true` if the specified range can accept the given replacements words.
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/// Returns `false` if the replacements words are already present in the original query
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/// or if there is fewer replacement words than the range to replace.
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//
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//
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// ## Ignored because already present in original
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//
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// new york city subway
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// -------- ^^^^
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// / \
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// [new york city]
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//
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//
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// ## Ignored because smaller than the original
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//
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// new york city subway
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// -------------
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// \ /
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// [new york]
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//
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//
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// ## Accepted because bigger than the original
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//
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// NYC subway
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// ---
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// / \
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// / \
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// / \
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// / \
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// / \
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// [new york city]
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//
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fn rewrite_range_with<S, T>(query: &[S], range: Range<usize>, words: &[T]) -> bool
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where
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S: AsRef<str>,
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T: AsRef<str>,
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{
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if words.len() <= range.len() {
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// there is fewer or equal replacement words
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// than there is already in the replaced range
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return false;
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}
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// retrieve the part to rewrite but with the length
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// of the replacement part
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let original = query.iter().skip(range.start).take(words.len());
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// check if the original query doesn't already contain
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// the replacement words
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!original
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.map(AsRef::as_ref)
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.eq(words.iter().map(AsRef::as_ref))
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}
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type Origin = usize;
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type RealLength = usize;
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#[derive(Debug)]
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struct FakeIntervalTree {
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intervals: Vec<(Range<usize>, (Origin, RealLength))>,
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}
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impl FakeIntervalTree {
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fn new(mut intervals: Vec<(Range<usize>, (Origin, RealLength))>) -> FakeIntervalTree {
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intervals.sort_unstable_by_key(|(r, _)| (r.start, r.end));
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FakeIntervalTree { intervals }
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}
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fn query(&self, point: usize) -> Option<(Range<usize>, (Origin, RealLength))> {
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let element = self.intervals.binary_search_by(|(r, _)| {
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if point >= r.start {
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if point < r.end {
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Equal
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} else {
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Less
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}
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} else {
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Greater
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}
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});
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let n = match element {
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Ok(n) => n,
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Err(n) => n,
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};
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match self.intervals.get(n) {
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Some((range, value)) if range.contains(&point) => Some((range.clone(), *value)),
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_otherwise => None,
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}
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}
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}
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pub struct QueryEnhancerBuilder<'a, S> {
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query: &'a [S],
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origins: Vec<usize>,
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real_to_origin: Vec<(Range<usize>, (Origin, RealLength))>,
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}
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impl<S: AsRef<str>> QueryEnhancerBuilder<'_, S> {
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pub fn new(query: &[S]) -> QueryEnhancerBuilder<S> {
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// we initialize origins query indices based on their positions
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let origins: Vec<_> = (0..=query.len()).collect();
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let real_to_origin = origins.iter().map(|&o| (o..o + 1, (o, 1))).collect();
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QueryEnhancerBuilder {
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query,
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origins,
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real_to_origin,
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}
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}
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/// Update the final real to origin query indices mapping.
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///
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/// `range` is the original words range that this `replacement` words replace
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/// and `real` is the first real query index of these replacement words.
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pub fn declare<T>(&mut self, range: Range<usize>, real: usize, replacement: &[T])
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where
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T: AsRef<str>,
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{
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// check if the range of original words
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// can be rewritten with the replacement words
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if rewrite_range_with(self.query, range.clone(), replacement) {
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// this range can be replaced so we need to
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// modify the origins accordingly
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let offset = replacement.len() - range.len();
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let previous_padding = self.origins[range.end - 1];
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let current_offset = (self.origins[range.end] - 1) - previous_padding;
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let diff = offset.saturating_sub(current_offset);
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self.origins[range.end] += diff;
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for r in &mut self.origins[range.end + 1..] {
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*r += diff;
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}
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}
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// we need to store the real number and origins relations
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// this way it will be possible to know by how many
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// we need to pad real query indices
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let real_range = real..real + replacement.len().max(range.len());
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let real_length = replacement.len();
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self.real_to_origin.push((real_range, (range.start, real_length)));
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}
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pub fn build(self) -> QueryEnhancer {
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let interval_tree = FakeIntervalTree::new(self.real_to_origin);
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let mut table = Vec::new();
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for real in 0.. {
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match replacement(&self.origins, &interval_tree, real) {
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Some(range) => table.push(range),
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None => break,
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}
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}
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QueryEnhancer { table }
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}
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}
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/// Returns the query indices that represent this real query index.
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fn replacement(
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origins: &[usize],
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real_to_origin: &FakeIntervalTree,
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real: u32,
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) -> Option<Range<u32>>
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{
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let real = real as usize;
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// query the fake interval tree with the real query index
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let (range, (origin, real_length)) = real_to_origin.query(real)?;
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// if `real` is the end bound of the range
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if (range.start + real_length - 1) == real {
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let mut count = range.len();
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let mut new_origin = origin;
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for (i, slice) in origins[new_origin..].windows(2).enumerate() {
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let len = slice[1] - slice[0];
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count = count.saturating_sub(len);
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if count == 0 {
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new_origin = origin + i;
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break;
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}
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}
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let n = real - range.start;
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let start = origins[origin];
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let end = origins.get(new_origin + 1)?;
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let remaining = (end - start) - n;
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Some(Range {
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start: (start + n) as u32,
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end: (start + n + remaining) as u32,
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})
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} else {
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// just return the origin along with
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// the real position of the word
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let n = real as usize - range.start;
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let origin = origins[origin];
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Some(Range {
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start: (origin + n) as u32,
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end: (origin + n + 1) as u32,
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})
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}
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}
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#[derive(Debug)]
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pub struct QueryEnhancer {
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table: Vec<Range<u32>>,
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}
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impl QueryEnhancer {
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/// Returns the query indices that represent this real query index.
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pub fn replacement(&self, real: u32) -> Range<u32> {
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self.table[real as usize].clone()
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn original_unmodified() {
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let query = ["new", "york", "city", "subway"];
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// 0 1 2 3
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let mut builder = QueryEnhancerBuilder::new(&query);
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// new york = new york city
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builder.declare(0..2, 4, &["new", "york", "city"]);
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// ^ 4 5 6
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..1); // new
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assert_eq!(enhancer.replacement(1), 1..2); // york
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assert_eq!(enhancer.replacement(2), 2..3); // city
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assert_eq!(enhancer.replacement(3), 3..4); // subway
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assert_eq!(enhancer.replacement(4), 0..1); // new
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assert_eq!(enhancer.replacement(5), 1..2); // york
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assert_eq!(enhancer.replacement(6), 2..3); // city
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}
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#[test]
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fn simple_growing() {
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let query = ["new", "york", "subway"];
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// 0 1 2
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let mut builder = QueryEnhancerBuilder::new(&query);
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// new york = new york city
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builder.declare(0..2, 3, &["new", "york", "city"]);
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// ^ 3 4 5
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..1); // new
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assert_eq!(enhancer.replacement(1), 1..3); // york
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assert_eq!(enhancer.replacement(2), 3..4); // subway
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assert_eq!(enhancer.replacement(3), 0..1); // new
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assert_eq!(enhancer.replacement(4), 1..2); // york
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assert_eq!(enhancer.replacement(5), 2..3); // city
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}
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#[test]
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fn same_place_growings() {
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let query = ["NY", "subway"];
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// 0 1
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let mut builder = QueryEnhancerBuilder::new(&query);
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// NY = new york
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builder.declare(0..1, 2, &["new", "york"]);
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// ^ 2 3
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// NY = new york city
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builder.declare(0..1, 4, &["new", "york", "city"]);
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// ^ 4 5 6
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// NY = NYC
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builder.declare(0..1, 7, &["NYC"]);
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// ^ 7
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// NY = new york city
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builder.declare(0..1, 8, &["new", "york", "city"]);
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// ^ 8 9 10
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// subway = underground train
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builder.declare(1..2, 11, &["underground", "train"]);
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// ^ 11 12
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..3); // NY
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assert_eq!(enhancer.replacement(1), 3..5); // subway
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assert_eq!(enhancer.replacement(2), 0..1); // new
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assert_eq!(enhancer.replacement(3), 1..3); // york
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assert_eq!(enhancer.replacement(4), 0..1); // new
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assert_eq!(enhancer.replacement(5), 1..2); // york
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assert_eq!(enhancer.replacement(6), 2..3); // city
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assert_eq!(enhancer.replacement(7), 0..3); // NYC
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assert_eq!(enhancer.replacement(8), 0..1); // new
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assert_eq!(enhancer.replacement(9), 1..2); // york
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assert_eq!(enhancer.replacement(10), 2..3); // city
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assert_eq!(enhancer.replacement(11), 3..4); // underground
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assert_eq!(enhancer.replacement(12), 4..5); // train
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}
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#[test]
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fn bigger_growing() {
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let query = ["NYC", "subway"];
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// 0 1
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let mut builder = QueryEnhancerBuilder::new(&query);
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// NYC = new york city
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builder.declare(0..1, 2, &["new", "york", "city"]);
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// ^ 2 3 4
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..3); // NYC
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assert_eq!(enhancer.replacement(1), 3..4); // subway
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assert_eq!(enhancer.replacement(2), 0..1); // new
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assert_eq!(enhancer.replacement(3), 1..2); // york
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assert_eq!(enhancer.replacement(4), 2..3); // city
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}
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#[test]
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fn middle_query_growing() {
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let query = ["great", "awesome", "NYC", "subway"];
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// 0 1 2 3
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let mut builder = QueryEnhancerBuilder::new(&query);
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// NYC = new york city
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builder.declare(2..3, 4, &["new", "york", "city"]);
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// ^ 4 5 6
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..1); // great
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assert_eq!(enhancer.replacement(1), 1..2); // awesome
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assert_eq!(enhancer.replacement(2), 2..5); // NYC
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assert_eq!(enhancer.replacement(3), 5..6); // subway
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assert_eq!(enhancer.replacement(4), 2..3); // new
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assert_eq!(enhancer.replacement(5), 3..4); // york
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assert_eq!(enhancer.replacement(6), 4..5); // city
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}
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#[test]
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fn end_query_growing() {
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let query = ["NYC", "subway"];
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// 0 1
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let mut builder = QueryEnhancerBuilder::new(&query);
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// NYC = new york city
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builder.declare(1..2, 2, &["underground", "train"]);
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// ^ 2 3
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..1); // NYC
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assert_eq!(enhancer.replacement(1), 1..3); // subway
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assert_eq!(enhancer.replacement(2), 1..2); // underground
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assert_eq!(enhancer.replacement(3), 2..3); // train
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}
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#[test]
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fn multiple_growings() {
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let query = ["great", "awesome", "NYC", "subway"];
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// 0 1 2 3
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let mut builder = QueryEnhancerBuilder::new(&query);
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// NYC = new york city
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builder.declare(2..3, 4, &["new", "york", "city"]);
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// ^ 4 5 6
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// subway = underground train
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builder.declare(3..4, 7, &["underground", "train"]);
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// ^ 7 8
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..1); // great
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assert_eq!(enhancer.replacement(1), 1..2); // awesome
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assert_eq!(enhancer.replacement(2), 2..5); // NYC
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assert_eq!(enhancer.replacement(3), 5..7); // subway
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assert_eq!(enhancer.replacement(4), 2..3); // new
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assert_eq!(enhancer.replacement(5), 3..4); // york
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assert_eq!(enhancer.replacement(6), 4..5); // city
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assert_eq!(enhancer.replacement(7), 5..6); // underground
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assert_eq!(enhancer.replacement(8), 6..7); // train
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}
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#[test]
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fn multiple_probable_growings() {
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let query = ["great", "awesome", "NYC", "subway"];
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// 0 1 2 3
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let mut builder = QueryEnhancerBuilder::new(&query);
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// NYC = new york city
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builder.declare(2..3, 4, &["new", "york", "city"]);
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// ^ 4 5 6
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// subway = underground train
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builder.declare(3..4, 7, &["underground", "train"]);
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// ^ 7 8
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// great awesome = good
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builder.declare(0..2, 9, &["good"]);
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// ^ 9
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// awesome NYC = NY
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builder.declare(1..3, 10, &["NY"]);
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// ^^ 10
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// NYC subway = metro
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builder.declare(2..4, 11, &["metro"]);
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// ^^ 11
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let enhancer = builder.build();
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assert_eq!(enhancer.replacement(0), 0..1); // great
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assert_eq!(enhancer.replacement(1), 1..2); // awesome
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assert_eq!(enhancer.replacement(2), 2..5); // NYC
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assert_eq!(enhancer.replacement(3), 5..7); // subway
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assert_eq!(enhancer.replacement(4), 2..3); // new
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assert_eq!(enhancer.replacement(5), 3..4); // york
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assert_eq!(enhancer.replacement(6), 4..5); // city
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assert_eq!(enhancer.replacement(7), 5..6); // underground
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assert_eq!(enhancer.replacement(8), 6..7); // train
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assert_eq!(enhancer.replacement(9), 0..2); // good
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assert_eq!(enhancer.replacement(10), 1..5); // NY
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assert_eq!(enhancer.replacement(11), 2..5); // metro
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}
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}
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