• 【Luogu】P2894酒店Hotel(线段树)


      题目链接

      我好蒻啊   题题看题解

      线段树维护从左端点开始的最长连续空房、右端点结束的最长连续空房、整段区间的最长连续空房、区间非空房的个数。

      http://blog.csdn.net/qq_39553725/article/details/77604572    此处题解。

      

    #include<cstdio>
    #include<cmath>
    #include<algorithm>
    #include<cstring>
    #include<iostream>
    #include<cctype>
    #define left (rt<<1)
    #define right (rt<<1|1)
    #define mid ((l+r)>>1)
    #define lson l,mid,left
    #define rson mid+1,r,right
    #define root 1,n,1
    #define len (r-l+1)
    
    inline long long max(long long a,long long b){    return a>b?a:b;    }
    
    inline long long read(){
        long long num=0,f=1;
        char ch=getchar();
        while(!isdigit(ch)){
            if(ch=='-')    f=-1;
            ch=getchar();
        }
        while(isdigit(ch)){
            num=num*10+ch-'0';
            ch=getchar();
        }
        return num*f;
    }
    
    int tag[1000010];
    struct Node{
        int linel,liner,linem,sum;
    }tree[1000010];
    
    inline void pushup(int rt,int m){
        tree[rt].linel=tree[left].sum?tree[left].linel:(m-(m>>1))+tree[right].linel;
        tree[rt].liner=tree[right].sum?tree[right].liner:(m>>1)+tree[left].liner;
        tree[rt].sum=tree[left].sum+tree[right].sum;
        tree[rt].linem=max(tree[rt].linel,tree[rt].liner);
        tree[rt].linem=max(tree[rt].linem,tree[left].liner+tree[right].linel);
        tree[rt].linem=max(tree[rt].linem,max(tree[left].linem,tree[right].linem));
    }
    
    inline void pushdown(int rt,int m){
        if(!tag[rt])    return;
        if(tag[rt]==1){
            tree[left].linel=tree[left].liner=tree[left].linem=0;tree[left].sum=(m-(m>>1));
            tree[right].linel=tree[right].liner=tree[right].linem=0;tree[right].sum=(m>>1);
            tag[left]=tag[right]=1;
            tag[rt]=0;
        }
        if(tag[rt]==2){
            tree[left].linel=tree[left].liner=tree[left].linem=(m-(m>>1));    tree[left].sum=0;
            tree[right].linel=tree[right].liner=tree[right].linem=(m>>1);    tree[right].sum=0;
            tag[left]=tag[right]=2;
            tag[rt]=0;
        }
    }
    
    void build(int l,int r,int rt){
        if(l==r){
            tree[rt]=(Node){1,1,1,0};
            return;
        }
        build(lson);
        build(rson);
        pushup(rt,len);
    }
    
    void clear(int from,int to,int l,int r,int rt){
        if(from<=l&&to>=r){
            tree[rt]=(Node){    len,len,len,0    };
            tag[rt]=2;
            return;
        }
        pushdown(rt,len);
        if(from<=mid)    clear(from,to,lson);
        if(to>mid)        clear(from,to,rson);
        pushup(rt,len);
        return;
    }
    
    void update(int from,int to,int l,int r,int rt){
        if(from<=l&&to>=r){
            tree[rt]=(Node){    0,0,0,len    };
            tag[rt]=1;
            return;
        }
        pushdown(rt,len);
        if(from<=mid)    update(from,to,lson);
        if(to>mid)        update(from,to,rson);
        pushup(rt,len);
        return;
    }
    
    int query(int size,int l,int r,int rt){
        if(tree[rt].linem<size)    return 0x7fffffff;
        pushdown(rt,len);
        if(tree[left].linem>=size)    return query(size,lson);
        if(tree[right].linel+tree[left].liner>=size)    return mid-tree[left].liner+1;
        if(tree[right].linem>=size)    return query(size,rson);
        return 0x7fffffff;
    }
    
    int main(){
        int n=read(),m=read();
        build(root);
        for(int i=1;i<=m;++i){
            int opt=read();
            if(opt==1){
                int x=read();
                int ans=query(x,root);
                if(ans==0x7fffffff){
                    printf("0
    ");
                    continue;
                }
                printf("%d
    ",ans);
                update(ans,ans+x-1,root);
            }
            if(opt==2){
                int x=read(),y=read();
                clear(x,x+y-1,root);
            }
        }
        return 0;
    }
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  • 原文地址:https://www.cnblogs.com/cellular-automaton/p/7756811.html
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