luogu2894 [USACO08FEB]酒店Hotel

#include <iostream>
#include <cstdio>
using namespace std;
int n, m, opt, uu, vv;
struct SGT{
    int lma[200005], rma[200005], sum[200005], tag[200005];
    //sum means there are how many empty rooms
    //tag==2 means these room should be clear, 1 means not
    void pushUp(int o, int l, int r, int lson, int rson, int mid){
        if(sum[lson]==mid-l+1)  lma[o] = mid - l + 1 + lma[rson];
        else    lma[o] = lma[lson];
        if(sum[rson]==r-mid)    rma[o] = r - mid + rma[lson];
        else    rma[o] = rma[rson];
        sum[o] = max(rma[lson] + lma[rson], max(sum[lson], sum[rson]));
    }
    void pushDown(int o, int l, int r, int lson, int rson, int mid){
        tag[lson] = tag[rson] = tag[o];
        sum[lson] = lma[lson] = rma[lson] = (mid - l + 1) * (tag[o] - 1);
        sum[rson] = lma[rson] = rma[rson] = (r - mid) * (tag[o] - 1);
        tag[o] = 0;
    }
    void build(int o, int l, int r){
        if(l==r)    lma[o] = rma[o] = sum[o] = 1;
        else{
            int mid=(l+r)>>1;
            int lson=o<<1;
            int rson=lson|1;
            if(l<=mid)  build(lson, l, mid);
            if(mid<r)   build(rson, mid+1, r);
            pushUp(o, l, r, lson, rson, mid);
        }
    }
    int query(int o, int l, int r, int x){
        if(l==r)    return l;
        else{
            int mid=(l+r)>>1;
            int lson=o<<1;
            int rson=lson|1;
            if(tag[o])  pushDown(o, l, r, lson, rson, mid);
            if(sum[lson]>=x)    return query(lson, l, mid, x);
            else if(rma[lson]+lma[rson]>=x) return mid-rma[lson]+1;
            else    return query(rson, mid+1, r, x);
        }
    }
    void modify(int o, int l, int r, int x, int y, int k){
        if(l>=x && r<=y){
            sum[o] = lma[o] = rma[o] = (r - l + 1) * (k - 1);
            tag[o] = k;
        }
        else{
            int mid=(l+r)>>1;
            int lson=o<<1;
            int rson=lson|1;
            if(tag[o])  pushDown(o, l, r, lson, rson, mid);
            if(x<=mid)  modify(lson, l, mid, x, y, k);
            if(mid<y)   modify(rson, mid+1, r, x, y, k);
            pushUp(o, l, r, lson, rson, mid);
        }
    }
}sgt;
int main(){
    cin>>n>>m;
    sgt.build(1, 1, n);
    while(m--){
        scanf("%d", &opt);
        if(opt==1){
            scanf("%d", &uu);
            if(sgt.sum[1]<uu)   printf("0\n");
            else{
                int ans=sgt.query(1, 1, n, uu);
                printf("%d\n", ans);
                sgt.modify(1, 1, n, ans, ans+uu-1, 1);
            }       
        }
        else{
            scanf("%d %d", &uu, &vv);
            sgt.modify(1, 1, n, uu, uu+vv-1, 2);
        }
    }
    return 0;
}