传送门
题意:动态加点,给定点询问曼哈顿距离最近的点
N,M≤3e5,x,y≤1e6N,M \leq 3e5,x,y \leq 1e6N,M≤3e5,x,y≤1e6
经(kan)过(le)分(ti)析(jie),这是一道cdqcdqcdq分治
考虑当前区间左半边修改对右半边的询问的影响
设左边某个修改为(x1,y1)(x_1,y_1)(x1,y1),右边的某个询问为(x2,y2)(x_2,y_2)(x2,y2)
考虑x1≤x2,y1≤y2x_1 \leq x_2,y_1 \leq y_2x1≤x2,y1≤y2的情况,答案为x2+y2−x1−y1x_2+y_2-x_1-y_1x2+y2−x1−y1
因为坐标是线性级别,所以需要排序搞掉一维
左右分别以xxx坐标排序
这样可以用双指针搞掉xxx的限制
yyy坐标开个树状数组,记录不超过yyy的修改中最大的x+yx+yx+y
然后很容易计算答案
其他三种情况类似
为了实现方便,直接旋转坐标系,即用infinfinf减
树状数组已经有了logloglog,我们已经无所畏惧,所以可以直接sortsortsort
复杂度O(NlogN2)O(Nlog_N^2)O(NlogN2)
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cctype>
#include <algorithm>
#define MAXN 600005
#define MAXM 2000005
#define MAX 1000000
using namespace std;
inline int read()
{int ans=0;char c=getchar();while (!isdigit(c)) c=getchar();while (isdigit(c)) ans=(ans<<3)+(ans<<1)+(c^48),c=getchar();return ans;
}
int n,m,siz;
struct BIT
{int s[MAXM];inline int lowbit(const int& x){return x&-x;}inline void modify(int x,const int& v){for (;x<=(MAX<<1);s[x]=max(s[x],v),x+=lowbit(x));}inline int query(int x){int ans=-0x3f3f3f3f;for (;x;ans=max(ans,s[x]),x-=lowbit(x));return ans;}inline void clear(int x){for (;x<=(MAX<<1);s[x]=-0x3f3f3f3f,x+=lowbit(x));}
}bit;
int ans[MAXN];
struct query{int type,x,y,pos;}q[MAXN];
inline bool operator <(const query& a,const query& b){if (a.x==b.x) return a.y<b.y;return a.x<b.x;}
void calc(int l,int r)
{int now=l-1,mid=(l+r)>>1;for (int i=mid+1;i<=r;i++){if (q[i].type==1) continue;while (now<mid&&q[now+1].x<=q[i].x) {++now;if (q[now].type==1) bit.modify(q[now].y,q[now].x+q[now].y);}ans[q[i].pos]=min(ans[q[i].pos],q[i].x+q[i].y-bit.query(q[i].y));}for (int i=l;i<=mid;i++) bit.clear(q[i].y);
}
void cdq(int l,int r)
{if (l==r) return;int mid=(l+r)>>1;cdq(l,mid);cdq(mid+1,r);calc(l,r);for (int i=l;i<=r;i++) q[i].x=MAX-q[i].x;sort(q+l,q+mid+1),sort(q+mid+1,q+r+1);calc(l,r);for (int i=l;i<=r;i++) q[i].y=MAX-q[i].y;sort(q+l,q+mid+1),sort(q+mid+1,q+r+1);calc(l,r);for (int i=l;i<=r;i++) q[i].x=MAX-q[i].x;sort(q+l,q+mid+1),sort(q+mid+1,q+r+1);calc(l,r);for (int i=l;i<=r;i++) q[i].y=MAX-q[i].y;sort(q+l,q+r+1);
}
int main()
{n=read(),m=read();for (int i=1;i<=n;i++) q[i].type=1,q[i].x=read()+1,q[i].y=read()+1;for (int i=1;i<=m;i++) q[n+i].type=read(),q[n+i].x=read()+1,q[n+i].y=read()+1,q[n+i].pos=i;memset(ans,0x3f,sizeof(ans));for (int i=0;i<MAXM;i++) bit.s[i]=-0x3f3f3f3f;cdq(1,n+m);for (int i=1;i<=m;i++)if (ans[i]<0x3f3f3f3f)printf("%d\n",ans[i]);return 0;
}