1048. Longest String Chain

class Solution {
    public int longestStrChain(String[] words) {
        Map<String, Integer> map = new HashMap<>();
        Arrays.sort(words, (w1, w2) -> w1.length() - w2.length());
        int longest = 1;
        for (String word : words) {
            int presentLen = 1;
            for (int i = 0; i < word.length(); i++) {
                StringBuilder sb = new StringBuilder(word);
                sb.deleteCharAt(i);
                String str = sb.toString();
                presentLen = Math.max(presentLen,  map.getOrDefault(str, 0) + 1);
            }
            map.put(word, presentLen);
            longest = Math.max(longest, presentLen);
        }
        return longest;
    }
}