bzoj3053 The Closest M Points
Posted wxyww
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调到哭系列
其实就是kd-tree的模板题。用堆维护出距离最小的m个点。然后在\(kd-tree\)上查询。
这一个小地方从上午10点调到下午4点半。。。。。真的快气哭了。。。
代码
//调的心累呀!!!!
/*
* @Author: wxyww
* @Date: 2019-06-13 09:57:42
* @Last Modified time: 2019-06-13 16:35:15
*/
#include<cstdio>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<queue>
#include<vector>
#include<ctime>
using namespace std;
typedef long long ll;
const int N = 500010,INF = 1e9;
#define ls TR[rt].ch[0]
#define rs TR[rt].ch[1]
#define pi pair<int,int>
ll read()
ll 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*10+c-'0';
c=getchar();
return x*f;
int D,WDK,tmp[N];
priority_queue<pi>q;
struct node
int ch[2],mx[6],mn[6],d[6];
TR[N],a[N],TMP;
int mul(int x)
return x * x;
void up(int rt)
for(int i = 0;i < WDK;++i)
TR[rt].mx[i] = TR[rt].mn[i] = TR[rt].d[i];
if(ls) TR[rt].mx[i] = max(TR[rt].mx[i],TR[ls].mx[i]),
TR[rt].mn[i] = min(TR[rt].mn[i],TR[ls].mn[i]);
if(rs) TR[rt].mx[i] = max(TR[rt].mx[i],TR[rs].mx[i]),
TR[rt].mn[i] = min(TR[rt].mn[i],TR[rs].mn[i]);
bool cmp(const node &A,const node &B)
return A.d[D] < B.d[D];
int build(int l,int r,int now)
if(l > r) return 0;
D = now;
int mid = (l + r) >> 1;
nth_element(a + l ,a + mid,a + r + 1,cmp);
int rt = mid;
TR[mid] = a[mid];
ls = build(l,mid - 1,(now + 1) % WDK);
rs = build(mid + 1,r,(now + 1) % WDK);
up(rt);
return rt;
int dis(const node &A,const node &B)
int ret = 0;
for(int i = 0;i < WDK;++i) ret += mul(A.d[i] - B.d[i]);
return ret;
int get(const node &A,const node &B)
int ret = 0;
for(int i = 0;i < WDK;++i)
ret += mul(max(0,A.d[i] - B.mx[i])) + mul(max(0,B.mn[i] - A.d[i]));
return ret;
void query(int rt)
if(!rt) return;
int K = dis(TR[rt],TMP);
if(K < q.top().first) q.pop(),q.push(make_pair(K,rt));
int dl = INF,dr = INF;
if(ls) dl = get(TMP,TR[ls]);
if(rs) dr = get(TMP,TR[rs]);
if(dl < dr)
if(dl < q.top().first) query(ls);
if(dr < q.top().first) query(rs);
else
if(dr < q.top().first) query(rs);
if(dl < q.top().first) query(ls);
int main()
// freopen("3053/1.in","r",stdin);
// freopen("m.out","w",stdout);
int n;
while(~scanf("%d%d",&n,&WDK))
// cout<<n<<" "<<WDK<<endl;
for(int i = 0;i < WDK;++i) a[0].mx[i] = -INF,a[0].mn[i] = INF;
for(int i = 1;i <= n;++i)
for(int j = 0;j < WDK;++j)
a[i].d[j] = read();
int root = build(1,n,0);
int T = read();
// puts("!!!");
while(T--)
for(int i = 0;i < WDK;++i) TMP.d[i] = read();
int m = read();
while(!q.empty()) q.pop();
for(int i = 1;i <= m;++i) q.push(make_pair(INF,0));
query(root);
for(int i = 1;i <= m;++i) tmp[i] = q.top().second,q.pop();
printf("the closest %d points are:\n",m);
for(int i = m;i >= 1;--i)
for(int j = 0;j < WDK - 1;++j)
printf("%d ",a[tmp[i]].d[j]);
printf("%d\n",a[tmp[i]].d[WDK - 1]);
return 0;
/*
6 2
2 9
6 9
4 4
7 5
8 1
9 6
1
5 1
*/
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