zoj 2326

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct paths
{
char x[21];
char y[21];
float dis;
}path[400];
int cmp(const void *a,const void *b) //这里注意啦，qsort返回值是int型的，必然不能返回两数的差值！！！
{
return (*(struct paths*)a).dis>(*(struct paths*)b).dis?1:-1;
}
int find(int x,int *father)
{
if(father[x]==x)
return x;
else
return find(father[x],father);
}
int main()
{
int m,n,j,father[400],i,A,B;
char a[400][21];
float len,count;
scanf("%f",&len);
scanf("%d",&n);
for(i=0;i<n;i++)
scanf("%s",a[i]);
for(i=0;i<n;i++)
father[i]=i;
scanf("%d",&m);
for(i=0;i<m;i++)
scanf("%s%s%f",&path[i].x,&path[i].y,&path[i].dis);
qsort(path,m,sizeof(path[0]),cmp);
for(i=0,count=0;i<m;i++)
{
for(j=0;j<n&&strcmp(a[j],path[i].x)!=0;j++)
{}
A=find(j,father);
for(j=0;j<n&&strcmp(a[j],path[i].y)!=0;j++)
{}
B=find(j,father);
if(A!=B)
{
father[A]=B;
count+=path[i].dis;
}
}
if(count<=len)
printf("Need %.1f miles of cable\n",count);
else
printf("Not enough cable\n");
return 0;
}