題目鏈接:http://acm.hdu.edu.cn/showproblem.php?pid=1875
這題我卡了10遍。。。
最終ac代碼:
#include<cstdio>
#include<iostream>
#include<cmath>
#define N 110
#include<cstring>
#define inf 0x3f3f3f3f
using namespace std;
int n;
double map[N][N],dis[N];
int x[N],y[N];
bool vis[N];
double dic(int i,int j) {
return sqrt(1.0*(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
}
void Prim() {
double minn,ans=0;
memset(vis,0,sizeof(vis));
vis[0]=1;
int k=0;
for(int i=0; i<n; i++)
dis[i]=map[0][i];
int i;
for( i=1; i<n; i++) {
minn=inf;
int j;
for(j=0; j<n; j++) {
if(!vis[j]&&dis[j]<minn) {
minn=dis[j];
k=j;
}
}
if(minn==inf) {
printf("oh!\n");
return;
}
ans+=minn;
vis[k]=1;
for(int j=0; j<n; j++)
if(!vis[j]&&dis[j]>map[k][j])
dis[j]=map[k][j];
}
printf("%.1lf\n",ans*100);
}
int main() {
int t;
scanf("%d",&t);
while(t--) {
scanf("%d",&n);
for(int i=0; i<n; i++)
scanf("%d%d",&x[i],&y[i] );
for(int i=0; i<n; i++)
for(int j=0; j<n; j++) {
map[i][j]=dic(i,j);
if(map[i][j]>1000||map[i][j]<10)
map[i][j]=inf;
}
Prim();
}
}