Class AhoCorasick

src/main/java/com/thealgorithms/strings/AhoCorasick.java:21–246

import java.util.Queue;

public final class AhoCorasick {
    private AhoCorasick() {
    }

    // Trie Node Class
    private static class Node {
        // Represents a character in the trie
        private final Map<Character, Node> child = new HashMap<>(); // Child nodes of the current node
        private Node suffixLink; // Suffix link to another node in the trie
        private Node outputLink; // Output link to another node in the trie
        private int patternInd; // Index of the pattern that ends at this node

        Node() {
            this.suffixLink = null;
            this.outputLink = null;
            this.patternInd = -1;
        }

        public Map<Character, Node> getChild() {
            return child;
        }

        public Node getSuffixLink() {
            return suffixLink;
        }

        public void setSuffixLink(final Node suffixLink) {
            this.suffixLink = suffixLink;
        }

        public Node getOutputLink() {
            return outputLink;
        }

        public void setOutputLink(final Node outputLink) {
            this.outputLink = outputLink;
        }

        public int getPatternInd() {
            return patternInd;
        }

        public void setPatternInd(final int patternInd) {
            this.patternInd = patternInd;
        }
    }

    // Trie Class
    public static class Trie {

        private Node root = null; // Root node of the trie
        private final String[] patterns; // patterns according to which Trie is constructed

        public Trie(final String[] patterns) {
            root = new Node(); // Initialize the root of the trie
            this.patterns = patterns;
            buildTrie();
            buildSuffixAndOutputLinks();