LeetCode 'Trie'

Trie.java

public class Trie {

        private static final char[] KEYS = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        private Map<Character, List<String>> data = new HashMap<>(KEYS.length);

        public Trie() {
            // init data
            for(Character key: KEYS) {
                data.put(key, new ArrayList<>());
            }
        }

        public void insert(String word) {
            List<String> bucket = data.get(word.charAt(0));
            bucket.add(word);
        }

        public boolean search(String word) {
            List<String> bucket = data.get(word.charAt(0));
            return bucket.contains(word);
        }

        public boolean startsWith(String prefix) {
            List<String> bucket = data.get(prefix.charAt(0));
            return bucket.stream().anyMatch(str -> str.startsWith(prefix));
        }
    }