九度oj 1541 二叉树

来源：互联网发布：方正综艺简体下载 mac 编辑：程序博客网时间：2024/05/20 01:44

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;}

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