【HDOJ】2295 Radar

  1 /* 2295 */
  2 #include <iostream>
  3 #include <string>
  4 #include <map>
  5 #include <queue>
  6 #include <set>
  7 #include <stack>
  8 #include <vector>
  9 #include <deque>
 10 #include <algorithm>
 11 #include <cstdio>
 12 #include <cmath>
 13 #include <ctime>
 14 #include <cstring>
 15 #include <climits>
 16 #include <cctype>
 17 #include <cassert>
 18 #include <functional>
 19 #include <iterator>
 20 #include <iomanip>
 21 using namespace std;
 22 //#pragma comment(linker,"/STACK:102400000,1024000")
 23 
 24 #define sti                set<int>
 25 #define stpii            set<pair<int, int> >
 26 #define mpii            map<int,int>
 27 #define vi                vector<int>
 28 #define pii                pair<int,int>
 29 #define vpii            vector<pair<int,int> >
 30 #define rep(i, a, n)     for (int i=a;i<n;++i)
 31 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 32 #define clr                clear
 33 #define pb                 push_back
 34 #define mp                 make_pair
 35 #define fir                first
 36 #define sec                second
 37 #define all(x)             (x).begin(),(x).end()
 38 #define SZ(x)             ((int)(x).size())
 39 #define lson            l, mid, rt<<1
 40 #define rson            mid+1, r, rt<<1|1
 41 
 42 const double eps = 1e-8;
 43 const int maxn = 60;
 44 int N, M, K;
 45 double cx[maxn], cy[maxn];
 46 double rx[maxn], ry[maxn];
 47 bool visit[maxn];
 48 
 49 typedef struct {
 50     static const int maxc = 65;
 51     static const int maxr = 65;
 52     static const int maxn = maxr * maxc;
 53 
 54     int n, sz;
 55     int S[maxc];
 56 
 57     int row[maxn], col[maxn];
 58     int L[maxn], R[maxn], U[maxn], D[maxn];
 59     
 60     int ansd;
 61     
 62     void init(int n_) {
 63         n = n_;
 64         
 65         rep(i, 0, n+1) {
 66             L[i] = i - 1;
 67             R[i] = i + 1;
 68             U[i] = i;
 69             D[i] = i;
 70             col[i] = i;
 71         }
 72         
 73         L[0] = n;
 74         R[n] = 0;
 75         
 76         ansd = INT_MAX;
 77         sz = n+1;
 78         memset(S, 0, sizeof(S));
 79     }
 80     
 81     void addRow(int r, vi columns) {
 82         int first = sz;
 83         int size = SZ(columns);
 84         
 85         rep(i, 0, size) {
 86             int c = columns[i];
 87             
 88             L[sz] = sz - 1;
 89             R[sz] = sz + 1;
 90             
 91             D[sz] = c;
 92             U[sz] = U[c];
 93             D[U[c]] = sz;
 94             U[c] = sz;
 95             
 96             row[sz] = r;
 97             col[sz] = c;
 98             
 99             ++S[c];
100             ++sz;
101         }
102         
103         L[first] = sz - 1;
104         R[sz - 1] = first;
105     }
106     
107     void remove(int c) {
108         for (int i=D[c]; i!=c; i=D[i]) {
109             L[R[i]] = L[i];
110             R[L[i]] = R[i];
111             --S[col[i]];
112         }
113     }
114     
115     void restore(int c) {
116         for (int i=D[c]; i!=c; i=D[i]) {
117             L[R[i]] = i;
118             R[L[i]] = i;
119             ++S[col[i]];
120         }
121     }
122     
123     int H() {
124         int ret = 0;
125         
126         memset(visit, false, sizeof(visit));
127         for (int i=R[0]; i!=0; i=R[i]) {
128             if (visit[col[i]])
129                 continue;
130             ++ret;
131             visit[col[i]] = true;
132             for (int j=D[i]; j!=i; j=D[j]) {
133                 for (int k=R[j]; k!=j; k=R[k]) {
134                     visit[col[k]] = true;
135                 }
136             }
137         }
138         
139         return ret;
140     }
141     
142     void dfs(int d) {
143         int delta = H();
144         
145         if (delta+d>=ansd || d+delta>K)
146             return ;
147         
148         if (R[0] == 0) {
149             ansd = min(ansd, d);
150             return ;
151         }
152         
153         int c = R[0];
154         for (int i=R[0]; i!=0; i=R[i]) {
155             if (S[i] < S[c])
156                 c = i;
157         }
158         
159         for (int i=D[c]; i!=c; i=D[i]) {
160             remove(i);
161             for (int j=R[i]; j!=i; j=R[j]) {
162                 remove(j);
163             }
164             dfs(d + 1);
165             if (ansd <= K)
166                 return ;
167             for (int j=L[i]; j!=i; j=L[j]) {
168                 restore(j);
169             }
170             restore(i);
171         }
172     }
173     
174 } DLX;
175 
176 DLX solver;
177 
178 double Length(int j, int i) {
179     return sqrt((cx[i]-rx[j])*(cx[i]-rx[j]) + (cy[i]-ry[j])*(cy[i]-ry[j]));
180 }
181 
182 bool judge(double bound) {
183     memset(visit, false, sizeof(visit));
184     solver.init(N);
185     
186     rep(i, 1, M+1) {
187         vi columns;
188         int cnt = 0;
189         rep(j, 1, N+1) {
190             if (Length(i, j) <= bound) {
191                 columns.pb(j);
192                 visit[j] = true;
193                 ++cnt;
194             }
195         }
196 
197         if (SZ(columns) > 0) {
198             solver.addRow(i, columns);
199         }
200     }
201     
202     rep(j, 1, N+1) {
203         if (!visit[j]) {
204     #ifndef ONLINE_JUDGE
205     // printf("ansd = %d\n", solver.ansd);
206     #endif
207             return false;
208         }
209     }
210     
211     solver.dfs(0);
212     
213     #ifndef ONLINE_JUDGE
214     // printf("ansd = %d\n", solver.ansd);
215     #endif
216     return solver.ansd<=K;
217 }
218 
219 int main() {
220     ios::sync_with_stdio(false);
221     #ifndef ONLINE_JUDGE
222         freopen("data.in", "r", stdin);
223         freopen("data.out", "w", stdout);
224     #endif
225 
226     double ans;
227     double l, r, mid;
228     int t;
229     
230     scanf("%d", &t);
231     while (t--) {
232         scanf("%d %d %d", &N, &M, &K);
233         rep(i, 1, N+1)
234             scanf("%lf %lf", &cx[i], &cy[i]);
235         rep(i, 1, M+1)
236             scanf("%lf %lf", &rx[i], &ry[i]);
237         l = 0;
238         r = ans = 2000.0;
239         while (r >= l) {
240             mid = (r + l) / 2.0;
241             if (judge(mid)) {
242                 ans = min(ans, mid);
243                 r = mid - eps;
244             } else {
245                 l = mid + eps;
246             }
247         }
248         printf("%.06lf\n", ans);
249     }
250 
251     #ifndef ONLINE_JUDGE
252         printf("time = %d.\n", (int)clock());
253     #endif
254 
255     return 0;
256 }