Note: This solution is combined with Trie + Generialized Abbreviation:

1. Since it looks for smallest one, we need persist a string to find minimum length.

2. Lots of mistakes:

                                index not moving (index++)

                                index is messed up. (s.charAt(index) - 'a')

                                data is not intialized.

class Solution {    class TrieNode {        TrieNode[] children = new TrieNode[26];        boolean isWord = false;    }        private TrieNode root;    private List
     
       result;    private String minL = "";    public String minAbbreviation(String target, String[] dictionary) {        if (dictionary.length == 0) return String.valueOf(target.length());        root = new TrieNode();        result = new ArrayList<>();        for (String s : dictionary) addWord(s);        generateComb(target, "", 0, 0);        for (String s : result) {            if (!search(s, root, 0, 0) && (minL.length() == 0 || s.length() < minL.length())) {                minL = s;            }        }        return minL;    }        private void addWord(String s) {        TrieNode current = root;        for (int i = 0; i < s.length(); i++) {            if (current.children[s.charAt(i) - 'a'] == null) {                current.children[s.charAt(i) - 'a'] = new TrieNode();            }            current = current.children[s.charAt(i) - 'a'];        }        current.isWord = true;    }        private boolean search(String s, TrieNode root, int index, int num) {        if (root == null) return false;        if (num > 0) {            for (int i = 0; i < 26; i++) {                if (search(s, root.children[i], index, num - 1)) return true;            }            return false;        }        if (index == s.length()) return root.isWord;        if (Character.isDigit(s.charAt(index))) {            int current = 0;            while (index < s.length() && Character.isDigit(s.charAt(index))) {                current = current * 10 + (s.charAt(index++) - '0');            }            return search(s, root, index, current);        }        return search(s, root.children[s.charAt(index) - 'a'], index + 1, num);    }        private void generateComb(String word, String current, int count, int index) {        if (index == word.length()) {            if (count > 0) {                current += String.valueOf(count);            }            result.add(current);            return;        }                generateComb(word, current, count + 1, index + 1);        generateComb(word, current + (count > 0 ? count : "") + word.charAt(index), 0, index + 1);    }}