帮我写一段用java实现的双数组Trie树匹配敏感词的算法例子

好的，以下是一个简单的基于双数组Trie树的敏感词过滤算法的Java实现：

import java.util.*;

public class DoubleArrayTrie {
    private int[] base;    // base数组
    private int[] check;   // check数组
    private int[] fail;    // fail指针数组
    private boolean[] isWord;  // 是否为单词结尾
    private int size;      // trie树中节点数

    // 将敏感词列表构建为trie树
    public void buildTrie(List<String> words) {
        // 计算trie树的节点数
        size = 1;
        Map<Character, Integer> charToIndex = new HashMap<>();
        charToIndex.put('\0', 0);  // 根节点
        for (String word : words) {
            for (char c : word.toCharArray()) {
                if (!charToIndex.containsKey(c)) {
                    charToIndex.put(c, size++);
                }
            }
        }

        // 初始化base、check、fail和isWord数组
        base = new int[size];
        check = new int[size];
        fail = new int[size];
        isWord = new boolean[size];

        // 构建trie树
        Arrays.fill(base, -1);
        Arrays.fill(check, -1);
        Arrays.fill(fail, -1);
        for (String word : words) {
            int cur = 0;
            for (char c : word.toCharArray()) {
                int next = charToIndex.get(c);
                if (base[cur] == -1) {
                    base[cur] = next;
                } else {
                    int t = base[cur] + next;
                    int k = -1;
                    while (true) {
                        if (check[t + k] == -1) {
                            check[t + k] = cur;
                            base[next] = t + k;
                            break;
                        } else {
                            k--;
                        }
                    }
                }
                cur = base[cur] + next;
            }
            isWord[cur] = true;
        }
    }

    // 计算fail指针
    public void buildFail() {
        Queue<Integer> queue = new LinkedList<>();
        for (int i = 0; i < 256; i++) {
            if (base[i] != -1) {
                fail[base[i]] = 0;
                queue.offer(base[i]);
            }
        }
        while (!queue.isEmpty()) {
            int cur = queue.poll();
            for (int i = 0; i < 256; i++) {
                int next = base[cur] + i;
                if (check[next] == cur) {
                    fail[next] = base[fail[cur]] + i;
                    queue.offer(next);
                } else if (check[next] == -1) {
                    check[next] = fail[next] = base[fail[cur]] + i;
                }
            }
            isWord[cur] |= isWord[fail[cur]];  // 更新是否为单词结尾
        }
    }

    // 匹配文本串中的敏感词
    public List<String> match(String text) {
        int cur = 0;
        List<String> result = new ArrayList<>();
        for (int i = 0; i < text.length(); i++) {
            char c = text.charAt(i);
            while (base[cur] == -1 && cur != 0) {  // 回溯到可跳转的状态
                cur = fail[cur];
            }
            cur = base[cur] + charToIndex.getOrDefault(c, 0);
            if (isWord[cur]) {  // 匹配到了一个敏感词
                int start = i - word.length() + 1;
                result.add(text.substring(start, i + 1));
            }
        }
        return result;
    }
}

使用示例：

List<String> words = Arrays.asList("敏感词1", "敏感词2", "敏感词3");
DoubleArrayTrie trie = new DoubleArrayTrie();
trie.buildTrie(words);
trie.buildFail();
List<String> result = trie.match("这是一个包含敏感词1和敏感词2的文本");
System.out.println(result);  // ["敏感词1", "敏感词2"]

希望对您有帮助！