[Medium] 820. The word compression coding

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Title Description

Trie prefix tree

First words in the string array descending order by length, followed by the reverse insertion Trie

class Solution {
    public int minimumLengthEncoding(String[] words) {
        if(words == null || words.length == 0){
            return 0;
        }
        Arrays.sort(words,(s1,s2)->s2.length()-s1.length());
        Trie root = new Trie();
        int res = 0;
        for(int i = 0; i < words.length ;i++){
            res += root.insert(words[i]);
        }
        return res;
    }
    
    class Trie{
        TrieNode root;
        
        public Trie(){
            root = new TrieNode();
        }
        public int insert(String str){//逆序插入
            char[] chars = str.toCharArray();
            boolean isNew = false;
            TrieNode cur = root;
            for(int i = chars.length-1 ; i >= 0 ;i-- ){
                if(cur.children[chars[i]-'a'] == null){
                    cur.children[chars[i]-'a'] = new TrieNode();
                    isNew = true;
                }
                cur = cur.children[chars[i]-'a'];
            }
            return isNew ? chars.length + 1 : 0;
        }
    }
    
    class TrieNode{
        char val;
        TrieNode[] children = new TrieNode[26];
        
        TrieNode(){}
    }
    
}