九度oj 1541 二叉树

原题链接：http://ac.jobdu.com/problem.php?pid=1541

简答题如下：

 1 #include<algorithm>

 2 #include<iostream>

 3 #include<cstring>

 4 #include<cstdlib>

 5 #include<cstdio>

 6 const int Max_N = 1100;

 7 struct Node{

 8     int v, s;

 9     Node *pre, *ch[2];

10     inline void set(int _v = 0, int _s = 0, Node *p = NULL){

11         v = _v, s = _s;

12         pre = ch[0] = ch[1] = p;

13     }

14     inline  void push_up(){

15         s = ch[0]->s + ch[1]->s + 1;

16     }

17     inline void link(Node *x, bool d){

18         ch[d] = x;

19         x->pre = this;

20     }

21 };

22 struct SplayTree{

23     Node *tail, *root, *null;

24     Node stack[Max_N], *ptr[Max_N];

25     void init(){

26         tail = &stack[0];

27         null = tail++;

28         null->set();

29         root = null;

30     }

31     inline  Node *newNode(int v){

32         Node *p = tail++;

33         p->set(v, 1, null);

34         return p;

35     }

36     inline void rotate(Node *x, int d){

37         Node *y = x->pre;

38         y->ch[!d] = x->ch[d];

39         if (x->ch[d] != null) x->ch[d]->pre = y;

40         x->pre = y->pre;

41         if (y->pre != null) y->pre->ch[y->pre->ch[0] != y] = x;

42         x->ch[d] = y;

43         y->pre = x;

44         y->push_up(), x->push_up();

45         if (y == root) root = x;

46     }

47     inline void update(Node *x){

48         if (x != null){

49             update(x->ch[0]);

50             update(x->ch[1]);

51             x->push_up();

52         }

53     }

54     void gogo(int n){

55         int i, a, b;

56         for (i = 0; i <= n; i++) ptr[i] = newNode(i);

57         for (i = 1; i <= n; i++){

58             scanf("%d %d", &a, &b);

59             if (-1 == a || -1 == b){

60                 if (-1 == a && b != -1) ptr[i]->link(ptr[b], 1);

61                 if (-1 == b && a != -1) ptr[i]->link(ptr[a], 0);

62             } else {

63                 ptr[i]->link(ptr[a], 0);

64                 ptr[i]->link(ptr[b], 1);

65             }

66             ptr[i]->push_up();

67             if (ptr[i]->pre == null) root = ptr[i];

68         }

69         update(root);

70     }

71     inline void work(){

72         int i, t;

73         char buf[50];

74         scanf("%d", &t);

75         while (t--){

76             scanf("%s %d", buf, &i);

77             if ('s' == buf[0]){

78                 printf("%d\n", ptr[i]->s);

79             } else if ('r' == buf[0]){

80                 if (ptr[i] == root) continue;

81                 rotate(ptr[i], ptr[i]->pre->ch[0] == ptr[i]);

82             } else {

83                 if (ptr[i] == root) printf("-1\n");

84                 else printf("%d\n", ptr[i]->pre->v);

85             }

86         }

87     }

88 }spt;

89 int main(){

90 #ifdef LOCAL

91     freopen("in.txt", "r", stdin);

92     freopen("out.txt", "w+", stdout);

93 #endif

94     int n;

95     while (~scanf("%d", &n)){

96         spt.init(), spt.gogo(n), spt.work();

97     }

98     return 0;

99 }

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