NYOJ1072我想回家_最短路径

原题地址：点击打开链接

此题略坑。。。

#include<stdio.h>
#include<string.h>
#include<math.h>
#define MAX 1<<31-1
struct Village
{
double x;
double y;
double r;
}village[110];
int used[110],n;
double dis[110],map[110][110],d;
bool judge(int u,int v,double &l)
{
int i;
Village v1=village[u];
Village v2=village[v];
l=sqrt((v1.x-v2.x)*(v1.x-v2.x)+(v1.y-v2.y)*(v1.y-v2.y));
if(l>(v1.r+v2.r) || l>d) //如果大于两圆的半径之和或者大于最长行走距离则排除
return false;
return true;
}
double djks(int s)
{
memset(used,0,sizeof(used));
int i,j,u;
double min;
for(i=1;i<=n;i++)
{
dis[i]=map[s][i];
}
dis[s]=0;
used[s]=1;
for(i=1;i<n;i++)
{
min=MAX;
u=-1; //重点！！！！！！
for(j=1;j<=n;j++)
{
if(dis[j]<min && used[j]!=1)
{
min=dis[j];
u=j;
}
}
if(u==-1)
return min;
used[u]=1;
for(j=1;j<=n;j++)
{
if(used[j]!=1 &&dis[j]>dis[u]+map[u][j])
{
dis[j]=dis[u]+map[u][j];
}
}
}
return dis
;
}
int main()
{
int i,j;
double l;
while(scanf("%d",&n)!=EOF)
{
for(i=0;i<=n;i++)
for(j=0;j<=n;j++)
map[i][j]=MAX;
for(i=1;i<=n;i++)
{
scanf("%lf%lf%lf",&village[i].x,&village[i].y,&village[i].r);
}
scanf("%lf%lf%lf",&village[0].x,&village[0].y,&village[0].r);
d=village[0].r;
for(i=1;i<n;i++)
{
for(j=i+1;j<=n;j++)
{
if(judge(i,j,l))
{
map[i][j]=l;
map[j][i]=l;
}
}
}
double res=djks(1);
if(res!=MAX)
printf("%.6lf\n",res);
else
printf("GAME OVER.\n");
}
return 0;
}
/*
3
0 0 3
10 10 1
1 1 3
1 1 4
*/