hdu 1875 畅通工程再续(最小生成树Prim)

/*Author: ACb0yDate: 2010-9-15Type: MSTProblemId: hdu 1875 畅通工程再续Result: AC*/#include <iostream>#include <cmath>using namespace std;#define inf 999999999.9struct Point {double x;double y;};int n;Point points[110];double g[110][110];double d[110];int vis[110];double get_dis(int a, int b) {return sqrt((points[a].x - points[b].x) * (points[a].x - points[b].x) +(points[a].y - points[b].y) * (points[a].y - points[b].y));}void MST_Prim() {int i, j;memset(vis, 0, sizeof(vis));for (i = 1; i <= n; i++) {d[i] = g[1][i];}d[1] = 0.0;double ans = 0.0;int flag = 1;for (i = 1; i <= n; i++) {double Min = inf;int pos = -1;for (j = 1; j <= n; j++) if (!vis[j]) {if (d[j] < Min) {Min = d[j];pos = j;}}if (Min == inf) {flag = 0;break;} ans += Min;vis[pos] = 1;for (j = 1; j <= n; j++) {if (g[pos][j] < d[j]) {d[j] = g[pos][j];}}}if (!flag) {cout << "oh!" << endl;} else {printf("%0.1lf/n", ans * 100);}}int main(){int cas;int i, j;#ifndef ONLINE_JUDGEfreopen("1875.txt", "r", stdin);#endifcin >> cas;while (cas--) {cin >> n;for (i = 1; i <= n; i++) {scanf("%lf%lf", &points[i].x, &points[i].y);}for (i = 1; i <= n; i++) {for (j = 1; j <= n; j++) {double temp = get_dis(i, j);if (temp >= 10.0 && temp <= 1000.0) {g[i][j] = g[j][i] = temp;} else {g[i][j] = g[j][i] = inf;}}}MST_Prim();}return 0;}