Struct LongestCommonSubsequence 

pub struct LongestCommonSubsequence { /* private fields */ }

The Longest Common Subsequence problem.

Given an alphabet of size k and a set of strings over {0, ..., k-1}, find a longest string w that is a subsequence of every input string.

Representation

The configuration is a vector of length max_length, where each entry is a symbol in {0, ..., alphabet_size}. The value alphabet_size is the padding symbol. Padding must be contiguous at the end of the vector. The effective subsequence consists of all non-padding symbols (the prefix before padding starts). The objective is to maximize the effective length.

Implementations

impl LongestCommonSubsequence

pub fn new(alphabet_size: usize, strings: Vec<Vec<usize>>) -> Self

Create a new LongestCommonSubsequence instance.

The max_length is computed automatically as the minimum of all string lengths (the maximum possible common subsequence length).

Panics

Panics if alphabet_size == 0 and any input string is non-empty, or if an input symbol is outside the declared alphabet, or if all strings are empty (max_length would be 0, requiring at least one non-empty string).

pub fn alphabet_size(&self) -> usize

Returns the alphabet size.

pub fn strings(&self) -> &[Vec<usize>]

Returns the input strings.

pub fn max_length(&self) -> usize

Returns the max_length field.

pub fn num_strings(&self) -> usize

Returns the number of input strings.

pub fn total_length(&self) -> usize

Returns the total input length across all strings.

pub fn sum_squared_lengths(&self) -> usize

Returns the sum of squared string lengths.

pub fn sum_triangular_lengths(&self) -> usize

Returns the sum of triangular numbers len * (len + 1) / 2 across strings.

pub fn num_transitions(&self) -> usize

Returns the number of adjacent position transitions.

pub fn cross_frequency_product(&self) -> usize

Returns the cross-frequency product: the sum over each alphabet symbol of the product of that symbol’s frequency across all input strings.

Formally: Σ_{c ∈ 0..alphabet_size} Π_{i=1..k} count(c, strings[i]) where count(c, s) is the number of occurrences of symbol c in string s.

This equals the exact number of match-node vertices in the LCS → MaxIS reduction graph.

Trait Implementations

impl Clone for LongestCommonSubsequence

fn clone(&self) -> LongestCommonSubsequence

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LongestCommonSubsequence

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for LongestCommonSubsequence

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Problem for LongestCommonSubsequence

const NAME: &'static str = "LongestCommonSubsequence"

Base name of this problem type (e.g., “MaximumIndependentSet”).

type Value = Max<usize>

The evaluation value type.

fn variant() -> Vec<(&'static str, &'static str)>

Returns variant attributes derived from type parameters.

fn dims(&self) -> Vec<usize>

Configuration space dimensions. Each entry is the cardinality of that variable.

fn evaluate(&self, config: &[usize]) -> Max<usize>

Evaluate the problem on a configuration.

fn num_variables(&self) -> usize

Number of variables (derived from dims).

fn problem_type() -> ProblemType

Look up this problem’s catalog entry.

impl ReduceTo<ILP> for LongestCommonSubsequence

type Result = ReductionLCSToILP

The reduction result type.

fn reduce_to(&self) -> Self::Result

Reduce this problem to the target problem type.

impl ReduceTo<LongestCommonSubsequence> for MinimumVertexCover<SimpleGraph, One>

type Result = ReductionVCToLCS

The reduction result type.

fn reduce_to(&self) -> Self::Result

Reduce this problem to the target problem type.

impl ReduceTo<MaximumIndependentSet<SimpleGraph, One>> for LongestCommonSubsequence

type Result = ReductionLCSToIS

The reduction result type.

fn reduce_to(&self) -> Self::Result

Reduce this problem to the target problem type.

impl Serialize for LongestCommonSubsequence

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl DeclaredVariant for LongestCommonSubsequence