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  • BZOJ 2716

    http://www.lydsy.com/JudgeOnline/problem.php?id=2716

    x坐标排序

    时间cdq分治

    y坐标树状数组维护

    对于每次询问左下角的点维护前缀最大值x+y

    然后坐标翻转做剩下三次操作

    #include<cstdio>
    #include<algorithm>
    #define gc getchar()
    #define FOR(i,s,t) for(register int i=s;i<=t;++i)
    using std::sort;
    inline int max(int a,int b){return a>b?a:b;}
    inline int min(int a,int b){return a<b?a:b;} 
    inline int abs(int x){return x>=0?x:-x;}
    const int N=1200011,M=4000011,inf=(1<<27);
    int ans[N];
    int n,m,maxx;
    struct point{
    	int x,y,t,k,pos;
    	inline bool operator<(point A)const{if(x!=A.x)return x<A.x;if(y!=A.y)return y<A.y; return t<A.t;}
    }p[N],t[N];
    namespace BIT{
    	int tr[M];
    	inline int lowbit(int x){return x&-x;}	
    	inline void add(int x,int v){for(;x<=maxx;x+=lowbit(x))tr[x]=max(tr[x],v);}
    	inline int query(int x){int ret=-inf;for(;x;x-=lowbit(x))ret=max(ret,tr[x]);return ret;}
    	inline void del(int x){for(;x<=maxx;x+=lowbit(x))if(tr[x]!=-inf)tr[x]=-inf;else break;}
    }
    using namespace BIT;
    inline void cdq(int l,int r){
    	if(l==r)return;
    	int mid=(l+r)>>1;
    	int j=l,k=mid+1;
    	FOR(i,l,r){
    		if(p[i].k==1&&p[i].t<=mid)add(p[i].y,(p[i].x+p[i].y));
    		if(p[i].k==2&&p[i].t>mid)ans[p[i].pos]=min(ans[p[i].pos],(p[i].x+p[i].y-query(p[i].y)));
    	}
    	FOR(i,l,r)if(p[i].k==1&&p[i].t<=mid)del(p[i].y);
    	FOR(i,l,r)p[i].t<=mid?t[j++]=p[i]:t[k++]=p[i];
    	FOR(i,l,r)p[i]=t[i];
    	cdq(l,mid);cdq(mid+1,r);
    }
    inline int read(){
    	char c;while(c=gc,c==' '||c=='
    ');int data=c-48;
    	while(c=gc,c>='0'&&c<='9')data=(data<<1)+(data<<3)+c-48;return data;
    }
    int main(){
    	n=read();m=read();
    	FOR(i,1,n){
    		p[i].t=i;p[i].k=1;
    		p[i].x=read();p[i].y=read();
    		maxx=max(maxx,max(abs(p[i].x),abs(p[i].y)));
    	}
    	FOR(i,(n+1),(n+m)){
    		p[i].k=read();p[i].x=read();p[i].y=read();
    		p[i].t=i;
    		maxx=max(maxx,max(abs(p[i].x),abs(p[i].y)));
    		if(p[i].k==2){
    			ans[++ans[0]]=inf;
    			p[i].pos=ans[0];
    		}
    	}
    	n+=m;
    	++maxx;
    	FOR(i,1,n)p[i].x+=maxx,p[i].y+=maxx;
    	maxx<<=1;
    	FOR(i,0,maxx)tr[i]=-inf;
    	sort(p+1,p+n+1);cdq(1,n);
    	FOR(i,1,n)p[i].y=maxx-p[i].y;sort(p+1,p+n+1);cdq(1,n);
    	FOR(i,1,n)p[i].x=maxx-p[i].x;sort(p+1,p+n+1);cdq(1,n);
    	FOR(i,1,n)p[i].y=maxx-p[i].y;sort(p+1,p+n+1);cdq(1,n);
    	FOR(i,1,ans[0])printf("%d
    ",ans[i]);
    	return 0;
    } 
    

      

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  • 原文地址:https://www.cnblogs.com/Stump/p/7997620.html
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