九度oj 1523 从上往下打印二叉树

原题链接：http://ac.jobdu.com/problem.php?pid=1523

建树，再层次遍历bfs。为了找根方便些，加了father指针。。。

如下：

 #include<algorithm>
 #include<iostream>
 #include<cstdlib>
 #include<cstring>
 #include<cstdio>
 #include<vector>
 #include<queue>
 using std::queue;
 using std::vector;
 using std::cin;
 const int Max_N = ;
 struct Node{
     int v;
     Node *f, *ch[];
     inline void set(int _v = , Node *p = NULL){
         v = _v, f = ch[] = ch[] = p;
     }
     inline void link(Node *x, bool d){
         ch[d] = x;
         x->f = this;
     }
 };
 struct BinaryTree{
     Node *tail, *root, *null;
     Node stack[Max_N], *ptr[Max_N];
     void init(){
         tail = &stack[];
         null = tail++;
         null->set();
         root = null;
     }
     inline Node *newNode(int v){
         Node *p = tail++;
         p->set(v, null);
         return p;
     }
     inline void gogo(int n){
         char c;
         int i, v, a, b;
         for (i = ; i <= n; i++){
             scanf("%d", &v);
             ptr[i] = newNode(v);
         }
         for (i = ; i <= n; i++){
             cin >> c;
             if (c == 'd'){
                 scanf("%d %d", &a, &b);
                 ptr[i]->link(ptr[a], );
                 ptr[i]->link(ptr[b], );
             } else if (c == 'l'){
                 scanf("%d", &a);
                 ptr[i]->link(ptr[a], );
             } else if (c == 'r'){
                 scanf("%d", &b);
                 ptr[i]->link(ptr[b], );
             } else {
                 ;
             }
             if (ptr[i]->f == null) root = ptr[i];
         }
     }
     inline void bfs(){
         queue<Node *> que;
         vector<int> ans;
         que.push(root);
         while (!que.empty()){
             Node *x = que.front();
             que.pop();
             ans.push_back(x->v);
             if (x->ch[] != null) que.push(x->ch[]);
             if (x->ch[] != null) que.push(x->ch[]);
         }
         int n = ans.size();
         for (int i = ; i < n; i++){
             printf("%d%c", ans[i], i < n -  ? ' ' : '\n');
         }
     }
 }tree;
 int main(){
 #ifdef LOCAL
     freopen("in.txt", "r", stdin);
     freopen("out.txt", "w+", stdout);
 #endif
     int n;
     while (~scanf("%d", &n)){
         tree.init(), tree.gogo(n), tree.bfs();
     }
     return ;
 }