[KD-TREE 堆] BZOJ 2626 JZPFAR

求第k远的点 大暴力啊

#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<queue>
using namespace std;
typedef long long ll;

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;
}

inline ll sqr(int x){ return (ll)x*x; }

const int N=100005;

int D;

struct node{
int d[2],mx[2],mn[2],l,r,idx;
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 ll dist(node A,node B) { return sqr(A[1]-B[1])+sqr(A[0]-B[0]); }
}tmp
;

int K,n;
struct abcd{
ll dis; int idx;
abcd(ll dis,int idx):dis(dis),idx(idx) { }
bool operator < (const abcd &B) const{
return dis==B.dis?idx<B.idx:dis>B.dis;
}
};

priority_queue<abcd> Q;

struct KDT{
node T
,now;
int root;
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;
}
ll Get(node A){
ll ret=0;
for(int i=0;i<2;i++)
ret+=max(sqr(A.mn[i]-now[i]),sqr(A.mx[i]-now[i]));
return ret;
}
void Que(int x){
abcd tmp=abcd(dist(T[x],now),T[x].idx);
if (tmp<Q.top())
Q.pop(),Q.push(tmp);
int l=T[x].l,r=T[x].r; ll dl=-1LL<<60,dr=-1LL<<60;
if(l) dl=Get(T[l]);
if(r) dr=Get(T[r]);
if(dl>dr){
if(dl>=Q.top().dis) Que(l);
if(dr>=Q.top().dis) Que(r);
}else {
if(dr>=Q.top().dis) Que(r);
if(dl>=Q.top().dis) Que(l);
}
}
}KD;

int main()
{
int ix,iy,Case;
freopen("t.in","r",stdin);
freopen("t.out","w",stdout);
read(n);
for (int i=1;i<=n;i++)
read(ix),read(iy),tmp[i]=node(ix,iy),tmp[i].idx=i;
KD.root=KD.Reb(1,n,0);
read(Case);
while (Case--)
{
read(ix); read(iy); read(K);
KD.now=node(ix,iy);
for (int i=1;i<=K;i++) Q.push(abcd(-1LL,0));
KD.Que(KD.root);
printf("%d\n",Q.top().idx);
while (!Q.empty()) Q.pop();
}
}