【bzoj2626】JZPFAR kd-tree

来源：互联网发布：ping网络命令编辑：程序博客网时间：2024/05/10 22:10
复习一下kd-tree模板，顺便学点新东西。
#include<cstdio>#include<cstring>#include<cstdlib>#include<cmath>#include<algorithm>#include<iostream>#include<queue>#define maxn 100010 using namespace std;int cur;struct yts1{long long dis;int id;};bool operator<(yts1 x,yts1 y){return x.dis>y.dis || (x.dis==y.dis && x.id<y.id);}struct yts{long long d[2],mx[2],mn[2],lch,rch;int id;long long& operator[](int x) {return d[x];}friend bool operator< (yts x,yts y) {return x[cur]<y[cur];}friend long long dis(yts x,yts y) {return (x[0]-y[0])*(x[0]-y[0])+(x[1]-y[1])*(x[1]-y[1]);}}t[maxn],p[maxn],T;int n,m,root,k;void update(int x){int l=t[x].lch,r=t[x].rch;for (int i=0;i<2;i++){t[x].mx[i]=t[x].mn[i]=t[x][i];if (l) t[x].mx[i]=max(t[x].mx[i],t[l].mx[i]);if (r) t[x].mx[i]=max(t[x].mx[i],t[r].mx[i]);if (l) t[x].mn[i]=min(t[x].mn[i],t[l].mn[i]);if (r) t[x].mn[i]=min(t[x].mn[i],t[r].mn[i]);}}int build_tree(int l,int r,int now){cur=now;int mid=(l+r)/2;nth_element(p+l,p+mid,p+r+1);t[mid]=p[mid];if (l<mid) t[mid].lch=build_tree(l,mid-1,now^1);if (mid<r) t[mid].rch=build_tree(mid+1,r,now^1);update(mid);return mid;}priority_queue<yts1> q;long long get_mx(int x){long long ans=0;for (int i=0;i<=1;i++) ans+=max((t[x].mx[i]-T[i])*(t[x].mx[i]-T[i]),(t[x].mn[i]-T[i])*(t[x].mn[i]-T[i]));return ans;}void query(int x){yts1 P,Q;P.dis=dis(t[x],T);P.id=t[x].id;Q=q.top();if (Q.dis<P.dis || (Q.dis==P.dis && Q.id>P.id)) q.pop(),q.push(P);int l=t[x].lch,r=t[x].rch;long long dl=-2,dr=-2;if (l) dl=get_mx(l);if (r) dr=get_mx(r);if (dl>dr){if (dl>=(q.top()).dis) query(l);if (dr>=(q.top()).dis) query(r);}else{if (dr>=(q.top()).dis) query(r);if (dl>=(q.top()).dis) query(l);}}int main(){scanf("%d",&n);for (int i=1;i<=n;i++) {scanf("%lld%lld",&p[i][0],&p[i][1]);p[i].id=i;}root=build_tree(1,n,0);scanf("%d",&m);while (m--){scanf("%lld%lld%d",&T[0],&T[1],&k);while (!q.empty()) q.pop();yts1 x;x.dis=-1;x.id=0;for (int i=1;i<=k;i++) q.push(x);query(root);printf("%d\n",(q.top()).id);//while (!q.empty()) {printf("%d %lld\n",(q.top()).id,(q.top()).dis);q.pop();}}return 0;}
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