poj 3667 Hotel 线段树区间合并

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至此，扫描线，线段树区间修改更新，可持久化线段树，线段树区间合并等线段树题目全部过了一遍。

接下来还有好多高级数据结构等着我去学。

trick：线段树区间合并时，cover只需一个，因为一段区间只能处于一种状态，我作死开了两个cover分别对应两种情况，

好处是一目了然，坏处是更新完一个cover还要更新另一个，（因为一段区间只能处于一种状态） QAQ

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <vector>#define mid ((l+r)/2)#define lson k<<1,l,mid#define rson k<<1|1,mid+1,r#define mk make_pairusing namespace std;const int maxn=50000+7;int siz[maxn*4];int lsiz[maxn*4],rsiz[maxn*4];int cover[maxn*4];  //outint cover2[maxn*4];  //invoid build(int k,int l,int r){    siz[k]=lsiz[k]=rsiz[k]=r-l+1;    cover[k]=0;    cover2[k]=0;    if(l==r)return ;    build(lson);    build(rson);}void push_up(int k,int l,int r){    siz[k]=max(siz[k<<1],max(siz[k<<1|1],rsiz[k<<1]+lsiz[k<<1|1]));    if(lsiz[k<<1]==mid-l+1){        lsiz[k]=lsiz[k<<1]+lsiz[k<<1|1];    }    else{        lsiz[k]=lsiz[k<<1];    }    if(rsiz[k<<1|1]==r-mid){        rsiz[k]=rsiz[k<<1|1]+rsiz[k<<1];    }    else {        rsiz[k]=rsiz[k<<1|1];    }}void push_down(int k,int l,int r){    if(cover[k]){        siz[k<<1]=lsiz[k<<1]=rsiz[k<<1]=mid-l+1;        siz[k<<1|1]=lsiz[k<<1|1]=rsiz[k<<1|1]=r-mid;        cover[k<<1]=cover[k<<1|1]=1;        cover[k]=0;        cover2[k<<1]=cover2[k<<1|1]=0;    }    if(cover2[k]){    siz[k<<1]=lsiz[k<<1]=rsiz[k<<1]=0;        siz[k<<1|1]=lsiz[k<<1|1]=rsiz[k<<1|1]=0;        cover2[k<<1]=cover2[k<<1|1]=1;        cover2[k]=0;        cover[k<<1]=cover[k<<1|1]=0;    }}void update(int k,int l,int r,int a,int b,int v){    if(a>r||b<l)return ;    if(a<=l&&r<=b){    if(v==1)    {siz[k]=lsiz[k]=rsiz[k]=r-l+1;cover[k]=1;cover2[k]=0;}    if(v==2)    {siz[k]=lsiz[k]=rsiz[k]=0;cover2[k]=1;cover[k]=0;}    return ;    }    push_down(k,l,r);    update(lson,a,b,v);    update(rson,a,b,v);    push_up(k,l,r);}int query(int k,int l,int r,int len){if(siz[k]<len)return 0;if(l==r)return l;if(lsiz[k]>=len)return l;push_down(k,l,r);if(siz[k<<1]>=len){return query(lson,len);}else if(rsiz[k<<1]+lsiz[k<<1|1]>=len){return mid-rsiz[k<<1]+1;}else return query(rson,len);}int main(){    int n,m;    while(~scanf("%d%d",&n,&m)){        build(1,1,n);        for(int i=1;i<=m;i++){            int t;            scanf("%d",&t);            if(t==1){            int num;scanf("%d",&num);                int tmp=query(1,1,n,num);                printf("%d\n",tmp);                if(tmp)                update(1,1,n,tmp,tmp+num-1,2);            }            else{            int l,d;scanf("%d%d",&l,&d);                update(1,1,n,l,l+d-1,1);            }        }    }    return 0;}

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