九度oj 1521 二叉树的镜像

  1 #include<algorithm>
  2 #include<iostream>
  3 #include<cstdlib>
  4 #include<cstring>
  5 #include<cstdio>
  6 #include<vector>
  7 using std::cin;
  8 using std::swap;
  9 using std::vector;
 10 const int Max_N = 1010;
 11 struct Node {
 12     int v, rev;
 13     Node *fa, *ch[2];
 14     inline void set(int _v, Node *p) {
 15         v = _v, rev = 0;
 16         fa = ch[0] = ch[1] = p;
 17     }
 18     inline void link(Node *x, bool d) {
 19         ch[d] = x;
 20         x->fa = this;
 21     }
 22     inline void update() {
 23         rev ^= 1;
 24         swap(ch[0], ch[1]);
 25     }
 26     inline void push_down() {
 27         if (rev != 0) {
 28             ch[0]->update();
 29             ch[1]->update();
 30             rev ^= 1;
 31         }
 32     }
 33 };
 34 struct BinaryTree {
 35     Node *root, *null, *tail, *ptr[Max_N], stack[Max_N];
 36     void init() {
 37         tail = &stack[0];
 38         null = tail++;
 39         null->set(0, NULL);
 40         root = null;
 41     }
 42     inline Node *newNode(int v) {
 43         Node *p = tail++;
 44         p->set(v, null);
 45         return p;
 46     }
 47     inline void gogo(int n) {
 48         char c;
 49         int i, v, a, b;
 50         for (i = 1; i <= n; i++) {
 51             scanf("%d", &v);
 52             ptr[i] = newNode(v);
 53         }
 54         for (i = 1; i <= n; i++) {
 55             cin >> c;
 56             if (c == ‘d‘){
 57                 scanf("%d %d", &a, &b);
 58                 ptr[i]->link(ptr[a], 0);
 59                 ptr[i]->link(ptr[b], 1);
 60             } else if (c == ‘l‘) {
 61                 scanf("%d", &a);
 62                 ptr[i]->link(ptr[a], 0);
 63             } else if (c == ‘r‘) {
 64                 scanf("%d", &b);
 65                 ptr[i]->link(ptr[b], 1);
 66             }
 67             if (ptr[i]->fa == null) root = ptr[i];
 68         }
 69     }
 70     inline void PreOder(Node *x, vector<int> &res) {
 71         if (x != null) {
 72             x->push_down();
 73             res.push_back(x->v);
 74             PreOder(x->ch[0], res);
 75             PreOder(x->ch[1], res);
 76         }
 77     }
 78     inline void PreOder() {
 79         vector<int> res;
 80         if (root == null) {
 81             puts("NULL");
 82             return;
 83         }
 84         root->update();
 85         PreOder(root, res);
 86         int n = res.size();
 87         for (int i = 0; i < n; i++) {
 88             printf("%d%c", res[i], i < n - 1 ? ‘ ‘ : ‘\n‘);
 89         }
 90     }
 91 }tree;
 92 int main() {
 93 #ifdef LOCAL
 94     freopen("in.txt", "r", stdin);
 95     freopen("out.txt", "w+", stdout);
 96 #endif
 97     int n;
 98     while (~scanf("%d", &n)) {
 99         tree.init();
100         tree.gogo(n);
101         tree.PreOder();
102     }
103     return 0;
104 }