【HDOJ】2966 In case of failure

KD树，这东西其实在ML经常被使用，不过30s的时限还是第一次见。

 /* 2966 */
 #include <iostream>
 #include <string>
 #include <map>
 #include <queue>
 #include <stack>
 #include <set>
 #include <vector>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 using namespace std;

 typedef struct {
     int x, y;
 } Point_t;

 typedef struct {
     int axis;
     Point_t p;
     int l, r;
 } node_t;

 const int maxn = 1e5+;
 Point_t P[maxn], P2[maxn];
 node_t nd[maxn];
 int L;
 __int64 ans;

 __int64 Eucl(Point_t a, Point_t b) {
     return 1LL*(a.x-b.x)*(a.x-b.x) + 1LL*(a.y-b.y)*(a.y-b.y);
 }

 bool compx(const Point_t &a, const Point_t &b) {
     return a.x < b.x;
 }

 bool compy(const Point_t &a, const Point_t &b) {
     return a.y < b.y;
 }

 void newNode() {
     ++L;
     nd[L].l = nd[L].r = ;
 }

 int create_KD(int l, int r, int d) {
     if (l > r)
         return ;
     newNode();
     int rt = L;
     nd[rt].axis = d&;
     if (l == r) {
         nd[rt].p = P[l];
         return rt;
     }
     if (d & )
         sort(P+l, P+r+, compy);
     else
         sort(P+l, P+r+, compx);
     int mid = (l+r)>>;
     nd[rt].p = P[mid];
     nd[rt].l = create_KD(l, mid-, d+);
     nd[rt].r = create_KD(mid+, r, d+);
     return rt;
 }

 void cal(int rt, Point_t p) {
     if (rt == )
         return ;
     int i, j, k;

     __int64 d = Eucl(nd[rt].p, p);
     if (d && d<ans)
         ans = d;

     if (nd[rt].axis) {
         j = nd[rt].p.y;
         k = p.y;
     } else {
         j = nd[rt].p.x;
         k = p.x;
     }

     if (k <= j)
         cal(nd[rt].l, p);
     else
         cal(nd[rt].r, p);

     if (1LL*(j-k)*(j-k) < ans) {
         if (k <= j)
             cal(nd[rt].r, p);
         else
             cal(nd[rt].l, p);
     }
 }

 int main() {
     int t, n;
     int i, j, k;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     scanf("%d", &t);
     while (t--) {
         scanf("%d", &n);
         for (i=; i<n; ++i) {
             scanf("%d %d", &P[i].x, &P[i].y);
             P2[i] = P[i];
         }
         L = ;
         int rt = create_KD(, n-, );
         for (i=; i<n; ++i) {
             ans = LLONG_MAX;
             cal(rt, P2[i]);
             printf("%I64d\n", ans);
         }
     }

     #ifndef ONLINE_JUDGE
         printf("time = %d\n", (int)(clock()));
     #endif

     return ;
 }