题目大意:给定平面上的n个点,定义距离为曼哈顿距离,支持下列操作:
1.插入一个点
2.查询离一个点最近的点的距离
Hint说KDTree【可以】过,那么不写KDT还能写啥= =
我的CDQ分治可是T掉了啊= =
记住KDT发生TLE事件的时候不一定是常数问题 有可能写挂了= =(这不和莫队一样么233
#include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #define M 500500 #define INF 0x3f3f3f3f using namespace std; struct Point{ int x,y; friend istream& operator >> (istream &_,Point &p) { scanf("%d%d",&p.x,&p.y); return _; } friend int Distance(const Point &p1,const Point &p2) { return abs(p1.x-p2.x) + abs(p1.y-p2.y) ; } }points[M]; int n,m; bool Compare_x(const Point &p1,const Point &p2) { return p1.x < p2.x ; } bool Compare_y(const Point &p1,const Point &p2) { return p1.y < p2.y ; } namespace K_Dimensional_Tree{ struct abcd{ abcd *ls,*rs; Point p; int x1,y1,x2,y2; abcd() {} abcd(const Point &_):p(_) { ls=rs=0x0; x1=x2=p.x; y1=y2=p.y; } void Push_Up(abcd *x) { x1=min(x1,x->x1); y1=min(y1,x->y1); x2=max(x2,x->x2); y2=max(y2,x->y2); } int Min_Distance(const Point &p) { int re=0; if(p.x<x1) re+=x1-p.x; if(p.x>x2) re+=p.x-x2; if(p.y<y1) re+=y1-p.y; if(p.y>y2) re+=p.y-y2; return re; } /* int Max_Distance(const Point &p) { int re=0; re+=max(p.x-x1,x2-p.x); re+=max(p.y-y1,y2-p.y); return re; } */ }mempool[M],*C=mempool,*root; void Build_Tree(abcd *&x,int l,int r,bool flag) { if(l>r) return ; int mid=l+r>>1; nth_element(points+l,points+mid,points+r+1,flag?Compare_y:Compare_x); x=new abcd(points[mid]); Build_Tree(x->ls,l,mid-1,flag^1); Build_Tree(x->rs,mid+1,r,flag^1); if(x->ls) x->Push_Up(x->ls); if(x->rs) x->Push_Up(x->rs); } void Insert(abcd *&x,const Point &p,bool flag) { if(!x) { x=new abcd(p); return ; } if( (flag?Compare_y:Compare_x)(p,x->p) ) { Insert(x->ls,p,flag^1); x->Push_Up(x->ls); } else { Insert(x->rs,p,flag^1); x->Push_Up(x->rs); } } void Get_Min(abcd *x,const Point &p,int &ans) { ans=min(ans,Distance(x->p,p)); int l_dis=x->ls?x->ls->Min_Distance(p):INF; int r_dis=x->rs?x->rs->Min_Distance(p):INF; if(l_dis<r_dis) { if( x->ls && l_dis<ans ) Get_Min(x->ls,p,ans); if( x->rs && r_dis<ans ) Get_Min(x->rs,p,ans); } else { if( x->rs && r_dis<ans ) Get_Min(x->rs,p,ans); if( x->ls && l_dis<ans ) Get_Min(x->ls,p,ans); } } } int main() { using namespace K_Dimensional_Tree; int i,o; Point p; cin>>n>>m; for(i=1;i<=n;i++) cin>>points[i]; Build_Tree(root,1,n,0); for(i=1;i<=m;i++) { scanf("%d",&o);cin>>p; if(o==1) Insert(root,p,0); else { int ans=INF; Get_Min(root,p,ans); printf("%d\n",ans); } } return 0; }
时间: 2024-10-09 19:08:30