HDU + 2295 + dancing + link ++

# Include <stdio. h> # include <string. h >#include <cmath> # define N 60 # define v n * N int L [V], R [V]; // record the two-way linked list int U [V], D [V]; // record the two-way linked list int C [V]; // The address int H [N] pointing to its column pointer header; // The row pointer header int S [N]; // records the total number of nodes in the column linked list int size, n, m, ak; int mark [N] [N], visit [N]; const double eps = 1e-7; void prepare (int c) {for (int I = 0; I <= c; I ++) {S [I] = 0; U [I] = D [I] = I; L [I + 1] = I; R [I] = I + 1;} R [c] = 0; size = c + 1; memset (H,-1, sizeof (H);} voi D Link (int r, int c) {S [c] ++; C [size] = c; U [size] = U [c]; D [U [c] = size; D [size] = c; U [c] = size; if (H [r] =-1) H [r] = L [size] = R [size] = size; else {L [size] = L [H [r]; R [L [H [r] = size; R [size] = H [r]; L [H [r] = size;} size ++ ;} void remove (int Size) {int j; for (j = D [Size]; j! = Size; j = D [j]) L [R [j] = L [j], R [L [j] = R [j];} void resume (int Size) {int j; for (j = D [Size]; j! = Size; j = D [j]) L [R [j] = R [L [j] = j;} int h () {int count = 0, i, j, k; memset (visit, 0, sizeof (visit); for (I = R [0]; I = R [I]) {if (visit [I]) continue; count ++; for (j = D [I]; j! = I; j = D [j]) {for (k = R [j]; k! = J; k = R [k]) visit [C [k] = 1;} return count;} void Dance (int k) {int I, j, min, c; if (k + h ()> = ak) return; if (! R [0]) {if (k <ak) ak = k; return;} for (min = N, I = R [0]; I; I = R [I]) if (min> S [I]) min = S [I], c = I; for (I = D [c]; I! = C; I = D [I]) {remove (I); for (j = R [I]; j! = I; j = R [j]) remove (j); Dance (k + 1); for (j = R [I]; j! = I; j = R [j]) resume (j); resume (I) ;}} struct point {double x, y;} rar [55], city [55]; double dis (point a, point B) {return sqrt (. x-b.x) * (. x-b.x) +. y-b.y) * (. y-b.y);} int main () {int ca, k, K; scanf ("% d", & ca); while (ca --) {scanf ("% d", & n, & m, & K); for (int I = 1; I <= n; I ++) scanf ("% lf", & city [I]. x, & city [I]. y); for (int I = 1; I <= m; I ++) scanf ("% lf", & rar [I]. x, & rar [I]. y); double L = 0, R = 10000, mid; while (R-L> eps) {prepare (n); mid = (R + L)/2.0; for (int I = 1; I <= m; I ++) {for (int j = 1; j <= n; j ++) {if (dis (rar [I], city [j]) <mid + eps) Link (I, j) ;}} ak = N + 1; Dance (0 ); // printf ("% d ###\ n", ak); if (ak> K) {L = mid;} else {R = mid ;}} printf ("%. 6lf \ n ", R);} return 0 ;}