【Leetcode1233】删除子文件夹

https://leetcode-cn.com/problems/remove-sub-folders-from-the-filesystem/comments/
愚蠢的做法，但是学了字典树。

class Solution {
public:
    vector<string> ans;
    struct Trie{
        int size_of_tree=0;int ch[400000][30],val[400000]={0};
        void init()
        {
            size_of_tree=1;
            memset(ch[0],0,sizeof(ch[0]));
        }
        void insert(string ss)
        {
            ss+='/';
            int l=ss.size(),now=0;
            for(int i=0;i<l;i++)
            {
                int index;
                if(ss[i]=='/')index=26;
                else index=ss[i]-'a';
                if(!ch[now][index])
                {
                    memset(ch[size_of_tree],0,sizeof(ch[size_of_tree]));
                    ch[now][index]=size_of_tree;
                    size_of_tree++;
                }
                now=ch[now][index];
            }
            val[now]=1;
        }
    }tree;
    void count(int node_index,string s)
    {
        for(int i=0;i<27;i++)
        {
            string tmps=s;
            int next_i=tree.ch[node_index][i];
            if(next_i)
            {
                if(i==26)tmps+='/';
                else tmps+=i+'a';
                if(tree.val[next_i])
                {
                    string ansstr;
                    int ls=tmps.size();
                    for(int j=0;j<ls-1;j++)
                    {
                        ansstr+=tmps[j];
                    }
                    ans.push_back(ansstr);
                }
                else
                {
                    count(next_i,tmps);
                }
            }
        }
        return;
    }
    vector<string> removeSubfolders(vector<string>& folder) {
        tree.init();
        int ll=folder.size();
        for(int i=0;i<ll;i++)
        {
            tree.insert(folder[i]);
        }
        string start;
        count(0,start);
        return ans;
    }
};