九度oj 1521 二叉树的镜像

原题链接：http://ac.jobdu.com/problem.php?pid=1521 
水题，如下。。

 #include<algorithm>
 #include<iostream>
 #include<cstdlib>
 #include<cstring>
 #include<cstdio>
 #include<vector>
 using std::cin;
 using std::swap;
 using std::vector;
 const int Max_N = ;
 struct Node {
     int v, rev;
     Node *fa, *ch[];
     inline void set(int _v, Node *p) {
         v = _v, rev = ;
         fa = ch[] = ch[] = p;
     }
     inline void link(Node *x, bool d) {
         ch[d] = x;
         x->fa = this;
     }
     inline void update() {
         rev ^= ;
         swap(ch[], ch[]);
     }
     inline void push_down() {
         if (rev != ) {
             ch[]->update();
             ch[]->update();
             rev ^= ;
         }
     }
 };
 struct BinaryTree {
     Node *root, *null, *tail, *ptr[Max_N], stack[Max_N];
     void init() {
         tail = &stack[];
         null = tail++;
         null->set(, NULL);
         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], );
             }
             if (ptr[i]->fa == null) root = ptr[i];
         }
     }
     inline void PreOder(Node *x, vector<int> &res) {
         if (x != null) {
             x->push_down();
             res.push_back(x->v);
             PreOder(x->ch[], res);
             PreOder(x->ch[], res);
         }
     }
     inline void PreOder() {
         vector<int> res;
         if (root == null) {
             puts("NULL");
             return;
         }
         root->update();
         PreOder(root, res);
         int n = res.size();
         for (int i = ; i < n; i++) {
             printf("%d%c", res[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.PreOder();
     }
     return ;
 }