Poj 2892 Tunnel Warfare

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一段区间上有一段连续的房子，每次可以消灭一个房子，修复一个房子，询问某一个房子所在的区间的长度

一个简单的线段树题

用splay写的话也很简单的，因为能正好对应splay的一些基本操作

(别人的板子是坠吼的

#include<cstdio>#include<iostream>#include<algorithm>#include<cstring>#include<stack>using namespace std;const int maxn = 51234;struct Node {Node*ch[2], *p;int size;Node() {size = 0;}bool d() {return this == p->ch[1];}void setc(Node*c, int d) {ch[d] = c;c->p = this;}void relax();void upd() {size = ch[0]->size + ch[1]->size + 1;}} Tnull, *null = &Tnull;Node mem[maxn];Node *make(int v) {    Node *C=&mem[v];C->ch[0] = C->ch[1] = null;C->size = 1;return C;}Node*build(int l, int r) {if (l > r)return null;int m = (l + r) >> 1;Node*t = make(m);t->setc(build(l, m-1), 0);t->setc(build(m + 1, r), 1);t->upd();return t;}Node*root;void rot(Node*t) {Node*p = t->p;int d = t->d();p->p->setc(t, p->d());p->setc(t->ch[!d], d);t->setc(p, !d);p->upd();if (p == root)root = t;}void splay(Node*t, Node*f = null) {while (t->p != f) {if (t->p->p == f)rot(t);elset->d() == t->p->d() ? (rot(t->p), rot(t)) : (rot(t), rot(t));}t->upd();}int n;int times[maxn];void dist(int id){    Node *rot = &mem[id];    splay(rot);    for(int i=0;i<2;i++){        if(rot->ch[i] != null){            rot->ch[i]->p=null;            rot->ch[i]=null;        }    }    rot->upd();    times[id]++;}int query(int id){    if(times[id] > 0)        return 0;    Node *rot = &mem[id];    splay(rot);    return rot->size;}void Link(int l,int r){    Node *L = &mem[l];    Node *R = &mem[r];    splay(L);    splay(R);    L->setc(R,1);    L->upd();}void fix(int id){    times[id]--;    if(times[id]!=0)        return;    if(id > 1 && times[id-1]==0){       Link(id-1,id);    }    if(id < n && times[id+1]==0){        Link(id,id+1);    }}stack<int> S;int main() {    int m;while(~scanf("%d %d",&n,&m)){        while(S.empty()==false)            S.pop();        memset(times,0,sizeof(times));        root = build(1, n);        root->p = null;        char ord[4];        int id;        while(m--){            scanf("%s",ord);            if(*ord == 'R'){                id = S.top();                S.pop();                fix(id);            }            else{                scanf("%d",&id);                if(*ord == 'Q'){                    printf("%d\n",query(id));                }                else{                    dist(id);                    S.push(id);                }            }        }}return 0;}

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