标签：des style http color os io strong for
| Time Limit: 1000MS | Memory Limit: 10000K | |
| Total Submissions: 2475 | Accepted: 755 |
Description
Input
Output
Sample Input
6 0 3 4 -1 -1 -1 -1 0 4 5 -1 -1 2 3 0 -1 -1 2 8 9 5 0 1 -1 7 2 1 -1 0 -1 5 -1 4 5 4 0 2 4 5 6 In the above input the last line indicates that "2" is the location of the fire and "4", "5" and "6" are the intersections where fire stations are located.
Sample Output
Org Dest Time Path 5 2 2 5 2 4 2 3 4 5 2 6 2 6 6 5 2
Source
题意：求各个消防点到失火点的距离和到达该点的路径。
思路：dijkstra求最短路，因为失火点只有一个，故可以求失火点到消防局的最短路，读入反向边。
#include"stdio.h"
#include"string.h"
#include"queue"
#include"algorithm"
using namespace std;
#define N 25
#define inf 0x7fffffff
int mark[N],g[N][N];
int dis[N],pre[N],n; //记录最短路，记录路线
struct node
{
int id,d; //记录消防局小标和距离
}a[N];
bool cmp(node a,node b)
{
return a.d<b.d;
}
void dijkstra(int s)
{
int i,min,u;
memset(pre,-1,sizeof(pre));
for(i=1;i<=n;i++)
{
pre[i]=s;
dis[i]=g[s][i];
mark[i]=0;
}
mark[s]=1;
while(1)
{
min=inf;
u=s;
for(i=1;i<=n;i++)
{
if(min>dis[i]&&!mark[i])
{
min=dis[i];
u=i;
}
}
if(u==s)
break;
mark[u]=1;
for(i=1;i<=n;i++)
{
if(!mark[i]&&g[u][i]<inf&&g[u][i]+dis[u]<dis[i])
{
dis[i]=g[u][i]+dis[u];
pre[i]=u;
}
}
}
}
void work(int k)
{
int i,j;
a[0].d=-1;
for(i=1;i<k;i++)
{
a[i].d=dis[a[i].id];
}
sort(a,a+k,cmp);
printf("Org Dest Time Path\n");
for(i=1;i<k;i++)
{
printf("%d %d %d %d ",a[i].id,a[0].id,a[i].d,a[i].id);
for(j=pre[a[i].id];j!=a[0].id;j=pre[j])
{
printf("%d ",j);
}
if(a[i].id!=a[0].id) //失火点和消防点相同
printf("%d\n",a[0].id);
else
printf("\n");
}
}
int main()
{
int i,j,t,k;
char str[500];
while(scanf("%d",&n)!=-1)
{
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
scanf("%d",&g[j][i]);
if(g[j][i]<0)
g[j][i]=inf;
}
}
gets(str);
gets(str);
t=k=0;
for(i=0;str[i]!='\0';i++)
{
if(str[i]>='0'&&str[i]<='9')
{
t=t*10+str[i]-'0';
}
else if(t!=0)
{
a[k++].id=t;
t=0;
}
}
if(t!=0) //末尾还有一个
a[k++].id=t;
memset(pre,-1,sizeof(pre));
dijkstra(a[0].id);
work(k);
}
return 0;
}
poj 1122 FDNY to the Rescue! （dijkstra）,布布扣,bubuko.com
poj 1122 FDNY to the Rescue! （dijkstra）
标签：des style http color os io strong for
原文地址：http://blog.csdn.net/u011721440/article/details/38663771
