洛谷P2894 [USACO08FEB]酒店Hotel_区间更新_区间查询

Code:

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int N = 200000+5;
int n,m,k;
struct Segment_Tree{
    int lazy,left,right,maxv;
}Seg[N<<2];
inline void push_down(int o,int l,int r)
{
    if(Seg[o].lazy == -1 || l==r)return;
    int mid = (l+r)>>1;
    int lz = Seg[o].lazy, ls=o<<1, rs=(o<<1)|1;
    Seg[ls].lazy = Seg[rs].lazy = lz;
    Seg[ls].maxv = lz==0 ? mid-l+1: 0;
    Seg[rs].maxv = lz==0 ?  r-mid:  0;
    Seg[ls].left = Seg[ls].right = Seg[ls].maxv;
    Seg[rs].left = Seg[rs].right = Seg[rs].maxv;
    Seg[o].lazy  = -1;
}
inline void update_seg(int o,int l,int r)
{
    int mid = (l+r)>>1, ls=o<<1, rs=(o<<1)|1;
    Seg[o].maxv  = max(Seg[ls].maxv, Seg[rs].maxv);
    Seg[o].maxv  = max(Seg[o].maxv, Seg[ls].right+Seg[rs].left);
    Seg[o].left  = Seg[ls].maxv == mid-l+1 ? Seg[ls].maxv+Seg[rs].left : Seg[ls].left;
    Seg[o].right = Seg[rs].maxv == r-mid   ? Seg[rs].maxv+Seg[ls].right: Seg[rs].right;
}
void build_Tree(int l,int r,int o){
    if(l>r)return;
    if(l==r)
    {
        Seg[o].left = Seg[o].right = Seg[o].maxv = 1;
        Seg[o].lazy = -1;
        return;
    }
    int mid = (l+r)>>1, ls=o<<1, rs=(o<<1)|1;
    build_Tree(l,mid,ls);
    build_Tree(mid+1,r,rs);
    update_seg(o,l,r);
    Seg[o].lazy = -1;
}
void update(int L,int R,int l,int r,int val,int o){
    if(L>R)return;
    if(L>=l&&R<=r)
    {
        Seg[o].lazy = val;
        Seg[o].maxv = (val==0)?R-L+1: 0;
        Seg[o].left = Seg[o].right = Seg[o].maxv;
        return;
    }
    push_down(o,L,R);
    int mid = (L+R)>>1,ls=o<<1, rs=(o<<1)|1;
    if(l<=mid) update(L,mid,l,r,val,ls);
    if(r>mid)  update(mid+1,R,l,r,val,rs);
    update_seg(o,L,R);
}
int query(int o,int l,int r){
    int mid=(l+r)>>1, ls=o<<1, rs=(o<<1)|1, ans;
    push_down(o,l,r);
    if(Seg[o].left >= k)
        ans = l;
	else if(Seg[ls].maxv >=k )
        ans = query(ls,l,mid);
	else if(Seg[ls].right+Seg[rs].left >= k)
        ans = mid+1-Seg[ls].right;
	else
        ans = query( rs ,mid+1,r);
    update_seg(o,l,r);
    return ans;
}
inline int solve_1(){
    if(Seg[1].maxv < k)return 0;
    return query(1,1,n);
}
int main()
{
  //  freopen("in.txt","r",stdin);
   // freopen("out.txt","w",stdout);
    scanf("%d%d",&n,&m);
    build_Tree(1,n,1);
    while(m--)
    {
        int op,x,y;
        scanf("%d%d",&op,&x);
        if(op==1)
        {
            k=x;
            int ans=solve_1();
            printf("%d\n",ans);
            if(ans!=0)update(1,n,ans,ans+k-1,1,1);
        }
        if(op==2)
        {
            scanf("%d",&y);
            update(1,n,x,x+y-1,0,1);
        }
    }
    return 0;
}