uva10397 Connect the Campus

来源：互联网发布：clock 算法编辑：程序博客网时间：2024/06/16 15:41

题意:

最小生成树,有的边已经不用考虑:

代码:

#include<cstdio>  #include<cstring>  #include<cmath>  #define N 760  double w[N][N],x[N],y[N],key[N];  int pre[N], hash[N], n, m;  inline double getDist(double x1,double y1,double x2,double y2){  return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));  }  double prim() {double u = 0xFFFFFFF;double sum = 0;memset(hash, 0, sizeof(hash));for(int i=1; i<=n; i++) {key[i] = w[1][i];}hash[1] = 1;for(int i=2; i<=n; i++) {u = 0xFFFFFFF;int x;for(int j=1; j<=n; j++) {if(!hash[j]) if(key[j]<u) {u = key[j];x = j;}}sum += key[x];hash[x] = 1;for(int j=1; j<=n; j++) {if(key[j] > w[x][j]) {key[j] = w[x][j];}}}return sum;}int main(){int u, v;while(~scanf("%d", &n)) {for(int i=1; i<=n; i++)scanf("%lf%lf", &x[i], &y[i]);for(int i=1; i<=n; i++)for(int j=1; j<=n; j++)if(i != j) {w[i][j] = getDist(x[i], y[i], x[j], y[j]);}scanf("%d", &m);for(int i=0; i<m; i++) {scanf("%d%d", &u, &v);w[u][v]=w[v][u]=0;}printf("%.2f\n", prim());}return 0;}

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