这题我用并查集 + map做，全RE。

调试了一下，父子关系似乎没错（？）

报错信息是double free or corruption （out)

bdfs无果，求调

#include <iostream>
#include <map>
#define N 500100
using namespace std;

map <string,string> p;
char op;
string name,dad;

string found(string k){
    if(k == p[k]) return k;
    else p[k] = found(p[k]);
}

void print(string str){
    int len = str.size();
    for(int i = 0;i < len;i ++){
        cout << str[i];
    }
}

int main(){

    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    while(cin >> op){
        if(op == '$') break;
        cin >> name;
        if(p[name] == "") p[name] = name;
        if(op == '#'){
            dad = name;
        }
        if(op == '+'){
            p[name] = dad;
        }
        if(op == '?'){
            print(name);cout << ' ';
            print(found(name)); cout << '\n';
        }
    }
    return 0;
}