九度oj 1541 二叉树

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

无力吐槽了，c语言中全局变量初始值不是0(指针就是空指针)么？

就这点害我re的快吐啦/(ㄒoㄒ)/~~。。。

题意没啥好说的，套splay tree做。具体如下：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define Max_N 1100
#define size(_) ((_)==null ? 0 : (_)->size)
typedef struct _spt{
    int val, size;
    struct _spt *pre, *ch[2];
}splay;
splay *root = NULL, *null = NULL, stack[Max_N], *ptr[Max_N];
int sz = 0;
splay *_calloc(int val){
    splay *p = &stack[sz++];
    p->val = val, p->size = 1;
    p->pre = p->ch[0] = p->ch[1] = null;
    return p;
}
void push_up(splay *x){
    if (x == null) return;
    x->size = size(x->ch[0]) + size(x->ch[1]) + 1;
}
void rotate(splay *x, int d){
    splay *y = x->pre;
    y->ch[!d] = x->ch[d];
    if (x->ch[d] != null) x->ch[d]->pre = y;
    x->pre = y->pre;
    if (y->pre != null) y->pre->ch[y->pre->ch[0] != y] = x;
    x->ch[d] = y;
    y->pre = x;
    push_up(y), push_up(x);
    if (y == root) root = x;
}
void initialize(){
    null = _calloc(-1);
    null->size = 0;
    root = null;
}
void update(splay *x){
    if (x != null){
        update(x->ch[0]);
        update(x->ch[1]);
        push_up(x);
    }
}
void gogo(int n){
    int i, a, b;
    for (i = 0; i <= n; i++){
        ptr[i] = _calloc(i);
    }
    for (i = 1; i <= n; i++){
        scanf("%d %d", &a, &b);
        if (-1 == a || -1 == b){
            if (-1 == a && b != -1) ptr[i]->ch[1] = ptr[b], ptr[b]->pre = ptr[i];
            if (-1 == b && a != -1) ptr[i]->ch[0] = ptr[a], ptr[a]->pre = ptr[i];
        } else {
            ptr[i]->ch[0] = ptr[a], ptr[a]->pre = ptr[i];
            ptr[i]->ch[1] = ptr[b], ptr[b]->pre = ptr[i];
        }
        push_up(ptr[i]);
        if (ptr[i]->pre == null) root = ptr[i];
    }
    update(root);
}
int main(){
#ifdef LOCAL
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w+", stdout);
#endif
    int n, t, i;
    char buf[50];
    while (~scanf("%d", &n)){
        sz = 0, initialize(), gogo(n);
        scanf("%d", &t);
        while (t--){
            scanf("%s %d", buf, &i);
            if (‘s‘ == buf[0]){
                printf("%d\n", ptr[i]->size);
            } else if (‘r‘ == buf[0]){
                if (ptr[i] == root) continue;
                rotate(ptr[i], ptr[i]->pre->ch[0] == ptr[i]);
            } else {
                if (ptr[i] == root) printf("-1\n");
                else printf("%d\n", ptr[i]->pre->val);
            }
        }
    }
    return 0;
}