Arctic Network---poj2349 minimum spanning tree

http://poj.org/problem?id=2349

Test instructions: There are n points given coordinates, between points and points can be radio or satellite communications, each point has a radio transceiver for radio communication, but only m points have satellite communication function. The distance of satellite communications can be infinitely large, but the distance of radio communication cannot exceed D, and the portion exceeding D will increase the cost of communication. To minimize the cost of communication.

In fact, is to seek a minimum spanning tree, m points have satellite communications, then there will be m-1 edge of the communication distance is infinite, in fact, this is the m-1 side without the cost calculation. The rest of the edges, find the maximum edge as the D value, so that all the remaining edges will not be greater than D, then no increase in communication costs. Save all the edge weights in the process of building the MST, then sort them in ascending order, removing the last m-1 (i.e. the largest m-1 edges, which use satellite communications), and the largest one is D.

The D array records the edges of the smallest spanning tree;

#include <stdio.h>#include<string.h>#include<map>#include<iostream>#include<algorithm>#include<math.h>#defineN 510#defineINF 0XFFFFFFFusing namespacestd;structnode{intx, y; DoubleD;} A[n],b[n*N];intCMP (node P,node q) {returnP.D <q.d;}intF[n];intFind (intx) {    if(x!=f[x]) f[x]=Find (f[x]); returnf[x];}intMain () {intT, M, N, I, J, K, p; Doubled[n*N]; scanf ("%d", &T);  while(t--) {scanf ("%d%d", &m, &N);  for(i=0; i<=n; i++) F[i]=i; Memset (A,0,sizeof(a)); memset (b,0,sizeof(b)); memset (d,0,sizeof(d));  for(i=1; i<=n; i++) scanf ("%d%d", &a[i].x, &a[i].y); K=0;  for(i=1; i<=n; i++)        {             for(j=1; j<i; J + +) {b[k].x=i; B[k].y=J; B[k++].D = sqrt ((a[i].x-a[j].x) * (a[i].x-a[j].x) + (A[I].Y-A[J].Y) * (a[i].y-a[j].y)); }} sort (b, B+K, CMP); P=0;  for(i=0; i<k; i++)        {            intPX =Find (b[i].x); intPY =Find (B[I].Y); if(px!=py) {F[PX]=py; D[p++] =B[I].D; }} printf ("%.2f\n", d[p-m]); }    return 0;}

Arctic Network---poj2349 minimum spanning tree