Code the Tree ZOJ - 1097

#include <cstdio>
#include <queue>
#include <vector>
#include <set>
#include <iostream>
using namespace std;

void parse(vector<set<int> >&adj,unsigned int p=0){
    unsigned int x;
    cin>>x;
    if(p){
        adj[x].insert(p);
        adj[p].insert(x);
    }

    while(true){
        char ch;
        cin>>ch;
        if(ch==‘)‘)
            break;
        parse(adj,x);
    }
    return ;
}

int main(){
    char ch;
    while(cin>>ch){
        vector<set<int> >adj(1020,set<int>());
        parse(adj);
        priority_queue<int,vector<int>,greater<int> >leafs;

        int n=0;
        for(int i=0;i<adj.size();i++){
            if(adj[i].size()!=0){
                n++;
                if(adj[i].size()==1){
                    leafs.push(i);
                }
            }
        }

        for(int k=1;k<n;k++){
            int x=leafs.top(); leafs.pop();

            if(k>1)
                cout<<" ";
            int p=*(adj[x].begin());
            cout<<p;
            adj[p].erase(x);
            if(adj[p].size()==1)
                leafs.push(p);
    }
     cout<<endl;
    }
    return 0;
}