hdu 1385 Minimum Transport Cost （floyd算法）

貌似····················

这个算法深的东西还是很不熟悉！继续学习！！！！

++++++++++++++++++++++++++++

============================

++++++++++++++++++++++++++++

-------------------------------------------------

============================

#include<stdio.h>

#include<string.h>
#define MAX 10000000

#define N 1001

int a[N][N],b[N],next[N][N];

int n,len;

void floyd()

{


int i,j,k,fee;


for(i=1;i<=n;i++)


for(j=1;j<=n;j++)


next[i][j]=j;


for(k=1;k<=n;k++)


{


for(i=1;i<=n;i++)


{


if(i==k||a[i][k]==-1)


continue;


for(j=1;j<=n;j++)


{


if(a[k][j]==-1||i==k||j==k)


continue;


fee=a[i][k]+a[k][j]+b[k];


if(a[i][j]==-1||a[i][j]>fee)


{


a[i][j]=fee;


next[i][j]=next[i][k];


}


else if(a[i][j]==fee)


{


if(next[i][j]>next[i][k])


next[i][j]=next[i][k];


}


}


}


}

}

void path(int start,int end)

{


if(end==next[start][end])


printf("%d-->%d\n",start,end);


else


{


printf("%d-->",start);


path(next[start][end],end);


}

}

int main()

{


int i,j,start,end;


while(scanf("%d",&n),n)


{


for(i=1;i<=n;i++)


for(j=1;j<=n;j++)


a[i][j]=MAX;


for(i=1;i<=n;i++)


for(j=1;j<=n;j++)


scanf("%d",&a[i][j]);


for(i=1;i<=n;i++)


scanf("%d",&b[i]);


floyd();


while(scanf("%d%d",&start,&end)!=EOF)


{

if(start==-1||end==-1)


break;


printf("From %d to %d :\n",start,end);


if(start==end)//特别注意：当始点与终点相同时的输出格式！


printf("Path: %d\n",start);


else


{


printf("Path: ");


path(start,end);


}


printf("Total cost : %d\n\n",a[start][end]);


}


}

return 0;

}

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1385