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。。

  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 }

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