HDU 1540 Tunnel Warfare(最长连续区间 基础)

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Tunnel Warfare

Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 6483    Accepted Submission(s): 2502

Problem Description

During the War of Resistance Against Japan, tunnel warfare was carried out extensively in the vast areas of north China Plain. Generally speaking, villages connected by tunnels lay in a line. Except the two at the ends, every village was directly connected with two neighboring ones.

Frequently the invaders launched attack on some of the villages and destroyed the parts of tunnels in them. The Eighth Route Army commanders requested the latest connection state of the tunnels and villages. If some villages are severely isolated, restoration of connection must be done immediately!

 

Input

The first line of the input contains two positive integers n and m (n, m ≤ 50,000) indicating the number of villages and events. Each of the next m lines describes an event.

There are three different events described in different format shown below:

D x: The x-th village was destroyed.

Q x: The Army commands requested the number of villages that x-th village was directly or indirectly connected with including itself.

R: The village destroyed last was rebuilt.

 

Output

Output the answer to each of the Army commanders’ request in order on a separate line.

 

 

Sample Input

7 9
D 3
D 6
D 5
Q 4
Q 5
R
Q 4
R
Q 4

Sample Output

1
0
2
4

 

/*
HDU 1540 Tunnel Warfare(最长连续区间 基础)

给你1-n连续的n个数字,然后执行以下三种操作
1.D x 删除第x个数字
2.R   恢复上一次删除的数字
3.Q x 查询包含x的最长连续区间

主要有ls,rs,ms分别表示当前节点 左端点开始的最长...,右端点...,整体最长连续区间
然后主要是在push_up和query上面了,要进行一些特殊判断来确定长度是否应该合并

hhh-2016-03-27 16:39:28
*/
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <functional>
using namespace std;
#define lson  (i<<1)
#define rson  ((i<<1)|1)
typedef long long ll;
const int maxn = 50050;
struct node
{
    int l,r;
    int ls,rs,ms;  //左端点,右端点,最大
    int mid()
    {
        return (l+r)>>1;
    }
} tree[maxn*5];

void push_up(int i)
{
    tree[i].ls = tree[lson].ls;
    tree[i].rs = tree[rson].rs;

    tree[i].ms = max(tree[lson].ms,tree[rson].ms);
    tree[i].ms = max(tree[i].ms,tree[rson].ls+tree[lson].rs);
    //i的ms肯定是lson,rson的ms.或者它们中间相连的长度
    if(tree[i].ls == tree[lson].r-tree[lson].l+1)
        //如果包含左儿子的全部,则与右儿子的ls相连
        tree[i].ls += tree[rson].ls;
    if(tree[i].rs == tree[rson].r-tree[rson].l+1)
        tree[i].rs += tree[lson].rs;
}

void build(int i,int l,int r)
{
    tree[i].l = l,tree[i].r = r;
    tree[i].ls=tree[i].rs=tree[i].ms=0;
    if(l ==r )
    {
        tree[i].ls=tree[i].rs=tree[i].ms=1;
        return ;
    }
    int mid=tree[i].mid();
    build(lson,l,mid);
    build(rson,mid+1,r);
    push_up(i);
}

void push_down(int i)
{

}

void Insert(int i,int k,int val)
{
    if(tree[i].l == tree[i].r)
    {
        if(val == 1)
            tree[i].ls=tree[i].rs=tree[i].ms=1;
        else
            tree[i].ls=tree[i].rs=tree[i].ms=0;
        return ;
    }
    push_down(i);
    int mid = tree[i].mid();
    if(k <= mid)
        Insert(lson,k,val);
    else
        Insert(rson,k,val);
    push_up(i);
}

int query(int i,int k)
{
    if(tree[i].l==tree[i].r || tree[i].ms==0 || tree[i].ms==(tree[i].r-tree[i].l+1))
        return tree[i].ms;

    int mid = tree[i].mid();
    if(k <= mid)
    {
        if(k >= tree[lson].r-tree[lson].rs+1)  //如果在rs的范围内,加上右儿子的ls(相连)
            return query(lson,k) + query(rson,mid+1);
        else
            return query(lson,k);
    }
    else
    {
        if(k <= tree[rson].ls+tree[rson].l-1)  //同理
            return query(rson,k)+query(lson,mid);
        else
            return query(rson,k);
    }
}

int qry[maxn];
char op[0];
int main()
{
    int n,x,q;
    int cas =1;
    while(scanf("%d%d",&n,&q) != EOF)
    {
        int tot = 0;
        build(1,1,n);
        for(int i = 1; i <= q; i++)
        {
            scanf("%s",op);
            if(op[0] == 'D')
            {
                scanf("%d",&x);
                qry[tot++] = x;
                Insert(1,x,-1);
            }
            else if(op[0] == 'R')
            {
                x = qry[--tot];
                Insert(1,x,1);
            }
            else
            {
                scanf("%d",&x);
                printf("%d\n",query(1,x));
            }
        }
    }
    return 0;
}