【HDU】2295 Radar

  1 #include<cstdio>

  2 #include<cstring>

  3 #include<cmath>

  4 #include<algorithm>

  5 #define MAXM 110

  6 #define MAXN 50000

  7 #define EPS 1e-8

  8 #define INF 0x7FFFFFFF

  9 using namespace std;

 10 int n, m, k, size;

 11 int L[MAXN], R[MAXN], U[MAXN], D[MAXN], C[MAXN];

 12 int H[MAXN], S[MAXN];

 13 bool vis[MAXM];

 14 struct Point {

 15     int x, y;

 16 };

 17 Point city[MAXM], radar[MAXM];

 18 inline int dbcmp(double x, double y) {

 19     if (fabs(x - y) < EPS)

 20         return 0;

 21     return x > y ? 1 : -1;

 22 }

 23 double DIS(int i, int j) {

 24     double x, y;

 25     x = city[i].x - radar[j].x;

 26     y = city[i].y - radar[j].y;

 27     return x * x + y * y;

 28 }

 29 void Init() {

 30     int i;

 31     for (i = 0; i <= m; i++)

 32         H[i] = -1;

 33     for (i = 0; i <= n; i++) {

 34         R[i] = i + 1;

 35         L[i + 1] = i;

 36         U[i] = D[i] = i;

 37         S[i] = 0;

 38     }

 39     R[n] = 0;

 40     size = n + 1;

 41 }

 42 void Link(int r, int c) {

 43     D[size] = D[c];

 44     U[size] = c;

 45     U[D[c]] = size;

 46     D[c] = size;

 47     if (H[r] < 0)

 48         H[r] = L[size] = R[size] = size;

 49     else {

 50         L[size] = H[r];

 51         R[size] = R[H[r]];

 52         L[R[H[r]]] = size;

 53         R[H[r]] = size;

 54     }

 55     S[c]++;

 56     C[size++] = c;

 57 }

 58 int A() {

 59     int i, j, k, res;

 60     memset(vis, false, sizeof(vis));

 61     for (res = 0, i = R[0]; i; i = R[i]) {

 62         if (vis[i])

 63             continue;

 64         res++;

 65         for (j = D[i]; j != i; j = D[j]) {

 66             for (k = R[j]; k != j; k = R[k])

 67                 vis[C[k]] = true;

 68         }

 69     }

 70     return res;

 71 }

 72 void Remove(int c) {

 73     int i;

 74     for (i = D[c]; i != c; i = D[i]) {

 75         L[R[i]] = L[i];

 76         R[L[i]] = R[i];

 77     }

 78 }

 79 void Resume(int c) {

 80     int i;

 81     for (i = D[c]; i != c; i = D[i])

 82         L[R[i]] = R[L[i]] = i;

 83 }

 84 bool Dance(int now) {

 85     if (R[0] == 0)

 86         return true;

 87     else if (now + A() <= k) {

 88         int i, j, temp, c;

 89         for (temp = INF,i = R[0]; i; i = R[i]) {

 90             if (temp > S[i]) {

 91                 temp = S[i];

 92                 c = i;

 93             }

 94         }

 95         for (i = D[c]; i != c; i = D[i]) {

 96             Remove(i);

 97             for (j = R[i]; j != i; j = R[j])

 98                 Remove(j);

 99             if (Dance(now + 1))

100                 return true;

101             for (j = L[i]; j != i; j = L[j])

102                 Resume(j);

103             Resume(i);

104         }

105     }

106     return false;

107 }

108 bool OK(double mid) {

109     int i, j;

110     Init();

111     mid *= mid;

112     for (i = 1; i <= n; i++) {

113         for (j = 1; j <= m; j++) {

114             if (dbcmp(DIS(i, j), mid) <= 0)

115                 Link(j, i);

116         }

117     }

118     return Dance(0);

119 }

120 int main() {

121     int T;

122     int i;

123     double low, high, mid;

124     scanf("%d", &T);

125     while (T--) {

126         scanf("%d%d%d", &n, &m, &k);

127         for (i = 1; i <= n; i++)

128             scanf("%d%d", &city[i].x, &city[i].y);

129         for (i = 1; i <= m; i++)

130             scanf("%d%d", &radar[i].x, &radar[i].y);

131         for (low = 0, high = 1e5; dbcmp(low, high) < 0;) {

132             mid = (low + high) / 2;

133             if (OK(mid))

134                 high = mid;

135             else

136                 low = mid;

137         }

138         printf("%.6lf\n", high);

139     }

140     return 0;

141 }