最短路

Time Limit: 5000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 42585    Accepted Submission(s): 18653

2 1
1 2 3
3 3
1 2 5
2 3 5
3 1 2
0 0

3
2

AC-code:

Dijkstra：

#include<cstdio>
#define max 0x3f3f3f3f
#define min(a,b) (a>b?b:a)
int n,dis[105],cost[105][105];
void dijkstra(int a)
{
	int i,vis[105];
	for(i=1;i<=n;i++)
	{
		dis[i]=max;
		vis[i]=0;
	}
	dis[a]=0;
	while(1)
	{
		int v=-1;
		for(i=1;i<=n;i++)
			if(!vis[i]&&(v==-1||dis[i]<dis[v]))
				v=i;
		if(v==-1)
			break;
		vis[v]=1;
		for(i=1;i<=n;i++)
			dis[i]=min(dis[i],dis[v]+cost[v][i]);
	}
}
int main()
{
	int m,i,j,a,b,c;
	while(scanf("%d%d",&n,&m),n||m)
	{
		for(i=1;i<=n;i++)
			for(j=1;j<=n;j++)
				cost[i][j]=max;
		for(i=1;i<=m;i++)
		{
			scanf("%d%d%d",&a,&b,&c);
			cost[a][b]=cost[b][a]=min(cost[a][b],c);	
		}
		dijkstra(1);
		printf("%d\n",dis[n]);
	}
	return 0;
}

 SPFA：

#include<cstdio>
#include<queue>
#include<cstring>
#define INF 0x3f3f3f3f
int dis[105],vis[105],n,head[105*105],num;
using namespace std;
struct node
{
	int from,to,val,next;
}A[105*105];
void spfa(int sx)
{
	queue<int>q;
	memset(dis,INF,sizeof(dis));
	memset(vis,0,sizeof(vis));
	q.push(sx);
	dis[sx]=0;
	vis[sx]=1;
	while(!q.empty())
	{
		int u=q.front();
		q.pop();
		vis[u]=0;
		for(int i=head[u];i!=-1;i=A[i].next)
		{
			int v=A[i].to;
			if(dis[v]>dis[u]+A[i].val)
			{
				dis[v]=dis[u]+A[i].val;
				if(!vis[v])
				{
					vis[v]=1;
					q.push(v);
				}
			}
		}
	}
	printf("%d\n",dis[n]);
}

void chan(int a,int b,int c)
{
	node B={a,b,c,head[a]};
	A[num]=B;
	head[a]=num++;
}
int main()
{
	int i,m,a,b,c;
	while(scanf("%d%d",&n,&m),n||m)
	{
		num=0;
		memset(head,-1,sizeof(head));
		for(i=0;i<m;i++)
		{
			scanf("%d%d%d",&a,&b,&c);
			chan(a,b,c);
			chan(b,a,c);
		}
		spfa(1);
	}
	return 0;
}