bzoj1593 [Usaco2008 Feb]Hotel 旅馆

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <cmath>

using namespace std;

const int maxn = 500010;

int n,m,lnum[maxn],rnum[maxn],maxx[maxn],len[maxn],flag[maxn];

void pushup(int o)
{
    lnum[o] = lnum[o * 2];
    rnum[o] = rnum[o * 2 + 1];
    if (lnum[o * 2] == len[o * 2])
    lnum[o] += lnum[o * 2 + 1];
    if (rnum[o * 2 + 1] == len[o * 2 + 1])
    rnum[o] += rnum[o * 2];
    maxx[o] = max(max(maxx[o * 2],maxx[o * 2 + 1]),rnum[o * 2] + lnum[o * 2 + 1]);
}

void build(int l,int r,int o)
{
    len[o] = r - l + 1;
    if (l == r)
    {
        lnum[o] = rnum[o] = maxx[o] = len[o];
        return;
    }
    int mid = (l + r) >> 1;
    build(l,mid,o * 2);
    build(mid + 1,r,o * 2 + 1);
    pushup(o);
}

void pushdown(int o)
{
    if (flag[o] == 1)
    {
        lnum[o * 2] = rnum[o * 2] = maxx[o * 2] = len[o * 2];
        lnum[o * 2 + 1] = rnum[o * 2 + 1] = maxx[o * 2 + 1] = len[o * 2 + 1];
        flag[o * 2] = flag[o * 2 + 1] = flag[o];
    }
    else
    if (flag[o] == 2)
    {
        lnum[o * 2] = rnum[o * 2] = maxx[o * 2] = lnum[o * 2 + 1] = rnum[o * 2 + 1] = maxx[o * 2 + 1] = 0;
        flag[o * 2] = flag[o * 2 + 1] = flag[o];
    }
    flag[o] = 0;
}

void update(int l,int r,int o,int x,int y,int d)
{
    if (x <= l && r <= y)
    {
        flag[o] = d + 1;
        if (d == 0)
        lnum[o] = rnum[o] = maxx[o] = len[o];
        else
        lnum[o] = rnum[o] = maxx[o] = 0;
        return;
    }
    pushdown(o);
    int mid = (l + r) >> 1;
    if (x <= mid)
    update(l,mid,o * 2,x,y,d);
    if (y > mid)
    update(mid + 1,r,o * 2 + 1,x,y,d);
    pushup(o);
}

int find(int l,int r,int o,int d)
{
    pushdown(o);
    if (l == r)
    return l;
    int mid = (l + r) >> 1;
    if (maxx[o * 2] >= d)
    return find(l,mid,o * 2,d);
    if (rnum[o * 2] + lnum[o * 2 + 1] >= d)
    return mid - rnum[o * 2] + 1;
    return find(mid + 1,r,o * 2 + 1,d);
}

int main()
{
    scanf("%d%d",&n,&m);
    build(1,n,1);
    for (int i = 1; i <= m; i++)
    {
        int op,x,d;
        scanf("%d",&op);
        if (op == 1)
        {
            scanf("%d",&d);
            //printf("%d\n",maxx[1]);
            if (maxx[1] >= d)
            {
            int cur = find(1,n,1,d);
            printf("%d\n",cur);
            update(1,n,1,cur,cur + d - 1,1);
            }
            else
            printf("0\n");
        }
        else
        {
            scanf("%d%d",&x,&d);
            update(1,n,1,x,x + d - 1,0);
        }
    }
    
    return 0;
}