[KD-TREE] BZOJ 1941 [Sdoi2010]Hide and Seek

题意：曼哈顿距离最大值与最小值的差

模板题

#include<cstdio>#include<cstdlib>#include<algorithm>using namespace std;inline char nc(){static char buf[100000],*p1=buf,*p2=buf;if (p1==p2) { p2=(p1=buf)+fread(buf,1,100000,stdin); if (p1==p2) return EOF; }return *p1++;}inline void read(int &x){char c=nc(),b=1;for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;}const int N=500005;int n,D;struct node{int d[2],mx[2],mn[2],l,r;node(int x=0,int y=0) { mx[0]=mn[0]=d[0]=x; mx[1]=mn[1]=d[1]=y; l=r=0; } int& operator[](int x) { return d[x]; }friend bool operator == (const node &A, const node &B) { return A.d[0]==B.d[0] && A.d[1]==B.d[1]; }friend bool operator < (const node &A,const node &B) { return A.d[D]<B.d[D]; }friend int dist(node A,node B) { return abs(A[1]-B[1])+abs(A[0]-B[0]); }}tmp[N];struct KDT{node T[N],now;int root,ans;void update(int x){int l=T[x].l,r=T[x].r;for(int i=0;i<2;i++){T[x].mn[i]=T[x].mx[i]=T[x][i];if(l) T[x].mn[i]=min(T[x].mn[i],T[l].mn[i]),T[x].mx[i]=max(T[x].mx[i],T[l].mx[i]);if(r) T[x].mn[i]=min(T[x].mn[i],T[r].mn[i]),T[x].mx[i]=max(T[x].mx[i],T[r].mx[i]);}}int Reb(int l,int r,int D){if (l>r) return 0;int mid=(l+r)>>1;::D=D; nth_element(tmp+l,tmp+mid,tmp+r+1);T[mid]=tmp[mid];T[mid].l=Reb(l,mid-1,D^1);T[mid].r=Reb(mid+1,r,D^1);update(mid); return mid;}int Get_mn(node A){int ret=0;for(int i=0;i<2;i++)ret+=max(now[i]-A.mx[i],0),ret+=max(A.mn[i]-now[i],0);return ret;}int Que_mn(int x){int tmp=dist(T[x],now);if (tmp) ans=min(ans,tmp);int l=T[x].l,r=T[x].r,dl=1<<30,dr=1<<30;if(l) dl=Get_mn(T[l]); if(r) dr=Get_mn(T[r]);if(dl<dr){if(dl<ans) Que_mn(l);if(dr<ans) Que_mn(r);}else {if(dr<ans) Que_mn(r);if(dl<ans) Que_mn(l);}return ans;}int Get_mx(node A){int ret=0;for(int i=0;i<2;i++)ret+=max(abs(now[i]-A.mx[i]),abs(now[i]-A.mn[i]));return ret;}int Que_mx(int x){int tmp=dist(T[x],now);if (tmp) ans=max(ans,tmp);int l=T[x].l,r=T[x].r,dl=-1<<30,dr=-1<<30;if(l) dl=Get_mx(T[l]);if(r) dr=Get_mx(T[r]);if(dl>dr){if(dl>ans) Que_mx(l);if(dr>ans) Que_mx(r);}else {if(dr>ans) Que_mx(r);if(dl>ans) Que_mx(l);}return ans;}}KD;int x[N],y[N];int ans=1<<30;int main(){int minimum,maximum;freopen("t.in","r",stdin);freopen("t.out","w",stdout);read(n);for (int i=1;i<=n;i++)read(x[i]),read(y[i]),tmp[i]=node(x[i],y[i]);KD.root=KD.Reb(1,n,0);for (int i=1;i<=n;i++){KD.now=node(x[i],y[i]);KD.ans=-1<<30; maximum=KD.Que_mx(KD.root);KD.ans= 1<<30; minimum=KD.Que_mn(KD.root);ans=min(ans,maximum-minimum);}printf("%d\n",ans);return 0;}