HDU 3790 (最短路)

 

Floyd 算法求解,结果超时;

超时代码:

#include <cstdio>
#include <cstring>
#define INF 0xfffffff
#define max 1010
int dist[max][max],mone[max][max];
int n,m;
void Floyd ()
{
	for (int k=1;k<=n;k++)
		for (int i=1;i<=n;i++)
		{
			if (dist[i][k] != INF)
				for (int j=1;j<=n;j++)
				{
					int tmp = dist[i][k]+dist[k][j];
					if (tmp < dist[i][j])
					{
						dist[i][j] = tmp;
						mone[i][j]= mone[i][k]+mone[k][j];
					}
					else if (tmp == dist[i][j] && mone[i][k]+mone[k][j] < mone[i][j])
						mone[i][j] = mone[i][k]+mone[k][j];
				}
		}
}
int main ()
{
	while (~scanf ("%d%d",&n,&m) && n && m)
	{
		int a,b,c,d;
		for (int i=1;i<n;i++)
			for (int j=i+1;j<=n;j++)
			{
				dist[i][j] = dist[j][i] = INF;
				mone[i][j] = mone[j][i] = INF;
			}
		for (int i=1;i<=n;i++)
		{
			dist[i][i]=0;
			mone[i][i]=0;
		}
		while (m--)
		{
			scanf ("%d%d%d%d",&a,&b,&c,&d);
			if (c < dist[a][b])
			{
				dist[a][b] = dist[b][a] = c;
				mone[a][b] = mone[b][a] = d;
			}
		}
		scanf ("%d%d",&a,&d);
		Floyd ();
		printf ("%d %d\n",dist[a][d],mone[a][d]);
	}
	return 0;
}

Dijkstra 算法;

AC代码:

#include <cstdio>
#include <cstring>
#define INF 0xfffffff
#define max 1010
struct Node
{
	int map[max][max];  //记录两个点之间的距离
	int val[max][max]; //记录两个点之间的花费
	int dist[max];    //记录点到原点的距离
	int mon[max];    //记录点到原点的花费
}graph;
int n,m;
bool mark[max];  //标记被访问的点。

void Dijkstra (int s)
{
	int k;
	memset (mark,0,sizeof (mark));
	for (int j=1;j<=n;j++)
	{
		graph.dist[j] = graph.map[s][j];
		graph.mon[j] = graph.val[s][j];
	}

	mark[s] = true;
	graph.dist[s] = 0;
	graph.mon[s] = 0;

	for (int i=1;i<=n;i++)
	{
		int min = INF;
		for (int j=1;j<=n;j++)
		{
			if (!mark[j] && graph.dist[j] < min)
				min=graph.dist[k=j];
		}
		mark[k] = true;
		for (int index=1;index<=n;index++)
		{
			if (!mark[index] && graph.map[k][index] != INF)
			{
				int tmp = graph.map[k][index] + graph.dist[k];
				if (tmp < graph.dist[index])
				{
					graph.dist[index] = tmp;
					graph.mon[index] = graph.mon[k]+graph.val[k][index];
				}
				else if (tmp == graph.dist[index] && graph.mon[k]+graph.val[k][index] < graph.mon[index])
				{
					graph.mon[index] = graph.mon[k]+graph.val[k][index];
				}
			}
		}
	}
}
int main ()
{
	while (~scanf ("%d%d",&n,&m) && n && m)
	{
		int a,b,c,d;
		for (int i=1;i<n;i++)
			for (int j=i+1;j<=n;j++)
			{
				graph.map[i][j] = graph.map[j][i] = INF;
				graph.val[i][j] = graph.val[j][i] = INF;
			}
		while (m--)
		{
			scanf ("%d%d%d%d",&a,&b,&c,&d);
			if (c < graph.map[a][b])
			{
				graph.map[a][b] = graph.map[b][a] = c;
				graph.val[a][b] = graph.val[b][a] = d;
			}
		}
		scanf ("%d%d",&a,&d);
		Dijkstra (a);
		printf ("%d %d\n",graph.dist[d],graph.mon[d]);
	}
	return 0;
}