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BZOJ2648 SJY擺棋子(KD-Tree)

  板子題。

#include<iostream> 
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
#define N 1000010
#define inf 2000000000
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'
||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;} int gcd(int n,int m){return m==0?n:gcd(m,n%m);} int read() { int x=0,f=1;char c=getchar(); while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();} while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();
return x*f; } int n,m,root,cnt,c,ans; struct point { int d[2],tag; bool operator <(const point&a) const { return d[c]<a.d[c]; } }a[N]; struct KDTree{int ch[2],a[2][2],tag;point p; }tree[N]; struct data{int op;point p; }q[N]; inline int dis(point u,point v){return abs(u.d[0
]-v.d[0])+abs(u.d[1]-v.d[1]);} inline void chkmin(int &x,int y){x=min(x,y);} inline void chkmax(int &x,int y){x=max(x,y);} inline bool isin(point x,int a[2][2]){return a[0][0]<=x.d[0]&&a[0][1]>=x.d[0]&&a[1][0]<=x.d[1]&&a[1][1]>=x.d[1];} inline int max(int x,int y,int z){return max(max(x,y),z);} inline int guess(point x,int a[2][2]){return max(0,a[0][0]-x.d[0],x.d[0]-a[0][1])+max(0,a[1][0]-x.d[1],x.d[1]-a[1][1]);} void build(int &k,int l,int r,int op) { if (l>r) return; k=++cnt;c=op;int mid=l+r>>1; nth_element(a+l,a+mid,a+r+1); tree[k].p=a[mid],tree[k].tag=a[mid].tag, tree[k].a[0][0]=tree[k].a[0][1]=a[mid].d[0], tree[k].a[1][0]=tree[k].a[1][1]=a[mid].d[1]; for (int i=l;i<=r;i++) chkmin(tree[k].a[0][0],a[i].d[0]),chkmax(tree[k].a[0][1],a[i].d[0]), chkmin(tree[k].a[1][0],a[i].d[1]),chkmax(tree[k].a[1][1],a[i].d[1]); build(tree[k].ch[0],l,mid-1,op^1); build(tree[k].ch[1],mid+1,r,op^1); } void ins(int k,point x) { if (!k) return; if (tree[k].p.d[0]==x.d[0]&&tree[k].p.d[1]==x.d[1]) {tree[k].tag=1;return;} if (isin(x,tree[tree[k].ch[0]].a)) ins(tree[k].ch[0],x); if (isin(x,tree[tree[k].ch[1]].a)) ins(tree[k].ch[1],x); } void query(int k,point x) { if (!k) return; if (tree[k].tag) chkmin(ans,dis(x,tree[k].p)); int p=tree[k].ch[0],q=tree[k].ch[1],u=guess(x,tree[p].a),v=guess(x,tree[q].a); if (v<u) swap(p,q),swap(u,v); if (u<ans) query(p,x); if (v<ans) query(q,x); } int main() { #ifndef ONLINE_JUDGE freopen("bzoj2648.in","r",stdin); freopen("bzoj2648.out","w",stdout); const char LL[]="%I64d\n"; #else const char LL[]="%lld\n"; #endif n=read(),m=read(); for (int i=1;i<=n;i++) a[i].d[0]=read(),a[i].d[1]=read(),a[i].tag=1; for (int i=1;i<=m;i++) { q[i].op=read(),q[i].p.d[0]=read(),q[i].p.d[1]=read(); if (q[i].op==1) a[++n]=q[i].p; } build(root,1,n,0); for (int i=1;i<=m;i++) if (q[i].op==1) ins(root,q[i].p); else ans=inf,query(root,q[i].p),printf("%d\n",ans); return 0; }