Hire and Fire(1)

namasuteさん(http://d.hatena.ne.jp/namasute0/20060728)がさらりとすんばらしいコードを書いてくださったので読んでみました。う〜ん、やってることは同じだと思うんだけど、ダメです。

試しにnamasuteさんのコードを参考に、C++で書き直してみたら、Runtime Error。なんでじゃ〜

#include<iostream>

#include<list>

#include<string>

#include<map>
using namespace std;
class Tree{

public:

    string name;

    Tree *parent;

    list<Tree*> children;

};
map<string, Tree*> mp;

char cmd[99],arg0[20],arg1[20],arg2[20];
void printLine(){

    int i;

    for(i=0;i<60;++i)printf("-");

    puts("");

}
void print(Tree*t,int node){

    for(int i=0;i<node;++i)cout<<"+";

    cout<<t->name<<endl;

    list<Tree*>::iterator p = t->children.begin();

    for(;p!=t->children.end();++p)print(*p,node+1);

}
void fired(Tree*t){

    if(t->children.empty()){

        list<Tree*>::iterator p = t->parent->children.begin();

        for(;p!=t->parent->children.end()&&(*p)->name!=t->name;++p);

        delete *p;

        t->parent->children.erase(p);

        return;

    }

    Tree *child;

    child = *(t->children.begin());

    t->name = child->name;

    fired(child);

    mp.insert(make_pair(t->name, t));

}
void fire(string name){

    map<string, Tree*>::iterator p;

    p = mp.find(name);

    fired(p->second);

}
void hire(string hirer, string hiree){

    Tree* t = new Tree();

    t->name = hiree;
    map<string, Tree*>::iterator p;

    p = mp.find(hirer);

    Tree *parent = p->second;

    t->parent = parent;

    parent->children.push_back(t);
    mp.insert(make_pair(hiree, t));

}
main(){

    gets(arg0);

    Tree* root = new Tree();

    root->name = arg0;

    mp.insert(make_pair(root->name, root));

    

    for(;gets(cmd);){

        switch(sscanf(cmd,"%s%s%s",arg0,arg1,arg2)){

            case 1: print(root, 0); printLine(); break;

            case 2: fire(arg1); break;

            case 3: hire(arg0, arg2); break;

        }

    }

    return 0;

}