学步园

//简单的搜索题<br /> #include<iostream><br /> #include<vector><br /> using namespace std;<br /> struct Node<br /> {<br /> char id;<br /> int left;<br /> int right;<br /> bool root;<br /> }node[1001];<br /> void print(int i)//递归打印先序遍历<br /> {<br /> if(i == 0) return;<br /> cout << node[i].id;<br /> print(node[i].left);<br /> print(node[i].right);<br /> }<br /> int main()<br /> {<br /> int n,index,root_num;<br /> //freopen("in.txt","r",stdin);<br /> //freopen("out.txt","w",stdout);<br /> while(cin >> n)<br /> {<br /> vector<int> v;<br /> while(n--)<br /> {<br /> cin >> index;<br /> v.push_back(index);<br /> cin >> node[index].id >> node[index].left >> node[index].right;<br /> node[index].root = 1;<br /> }<br /> for(int i = 0;i < v.size();i++)<br /> {<br /> int l = node[v[i]].left,r = node[v[i]].right;<br /> node[l].root = 0;<br /> node[r].root = 0;<br /> }//将有被指向的结点将root置零，表示不是根节点。则最后没有被置零的为根节点<br /> for(int i = 0;i < v.size();i++)<br /> {<br /> if(node[v[i]].root == 1)<br /> root_num = v[i];<br /> }//找出根节点<br /> print(root_num);//打印<br /> cout << endl;<br /> }<br /> return 0;<br /> }