Struct LcsTable

pub struct LcsTable<'a, T: 'a> { /* private fields */ }

Implementations

impl<'a, T> LcsTable<'a, T>

where T: Eq,

Finding longest common subsequences (“LCS”) between two sequences requires constructing a n x m table (where the two sequences are of lengths n and m). This is expensive to construct and there’s a lot of stuff you can calculate using it, so LcsTable holds onto this data.

pub fn new(a: &'a [T], b: &'a [T]) -> LcsTable<'a, T>

Constructs a LcsTable for matching between two sequences a and b.

pub fn longest_common_subsequence(&self) -> Vec<(&T, &T)>

Gets the longest common subsequence between a and b. Returned elements are in the form (elem_a, elem_b), where elem_a is a reference to an element in a, elem_b is a reference to an element in b, and elem_a == elem_b.

Example:

use lcs::LcsTable;

let a: Vec<_> = "a--b---c".chars().collect();
let b: Vec<_> = "abc".chars().collect();

let table = LcsTable::new(&a, &b);
let lcs = table.longest_common_subsequence();

assert_eq!(vec![(&'a', &'a'), (&'b', &'b'), (&'c', &'c')], lcs);

pub fn longest_common_subsequences(&self) -> HashSet<Vec<(&T, &T)>>

where T: Hash,

Gets all longest common subsequences between a and b. Returned elements are in the form (elem_a, elem_b), where elem_a is a reference to an element in a, elem_b is a reference to an element in b, and elem_a == elem_b.

Example:

use lcs::LcsTable;

let a: Vec<_> = "gac".chars().collect();
let b: Vec<_> = "agcat".chars().collect();

let table = LcsTable::new(&a, &b);
let subsequences = table.longest_common_subsequences();
assert_eq!(3, subsequences.len());
assert!(subsequences.contains(&vec![(&'a', &'a'), (&'c', &'c')]));
assert!(subsequences.contains(&vec![(&'g', &'g'), (&'a', &'a')]));
assert!(subsequences.contains(&vec![(&'g', &'g'), (&'c', &'c')]));

pub fn diff(&self) -> Vec<DiffComponent<&T>>

Computes a diff from a to b.

Example

use lcs::{DiffComponent, LcsTable};

let a: Vec<_> = "axb".chars().collect();
let b: Vec<_> = "abc".chars().collect();

let table = LcsTable::new(&a, &b);
let diff = table.diff();
assert_eq!(diff, vec![
    DiffComponent::Unchanged(&'a', &'a'),
    DiffComponent::Deletion(&'x'),
    DiffComponent::Unchanged(&'b', &'b'),
    DiffComponent::Insertion(&'c')
]);

Trait Implementations

impl<'a, T: Debug + 'a> Debug for LcsTable<'a, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.