【图论之最短路】杭电 hdu 2544 最短路

 

 

Dijkstra 算法

 

/* THE PROGRAM IS MADE BY PYY */
/*----------------------------------------------------------------------------//
	Copyright (c) 2011 panyanyany All rights reserved.

	URL   : http://acm.hdu.edu.cn/showproblem.php?pid=2544
	Name  : 2544 最短路

	Date  : Thursday, January 5, 2012
	Time Stage : half an hour

	Result: 
5231194	2012-01-05 17:06:37	Accepted	2544
15MS	228K	1573 B
C++	pyy


Test Data :

Review :

//----------------------------------------------------------------------------*/

#include <stdio.h>
#include <string.h>

#define min(x, y)	((x) < (y) ? (x) : (y))
#define max(x, y)	((x) > (y) ? (x) : (y))

#define INF		0x3f3f3f3f
#define MAXN	102

int		n, m ;
int		map[MAXN][MAXN], dest[MAXN] ;
bool	used[MAXN] ;

int dijkstra (const int start, const int end)
{
	int i, j ;
	int iMinPath, MinPath ;

	memset (used, 0, sizeof (used)) ;
	memset (dest, INF, sizeof (dest)) ;

	for (i = start ; i <= end ; ++i)
		dest[i] = map[start][i] ;

	used[start] = true ;

	for (i = 1 ; i <= n ; ++i)
	{
		MinPath = INF ;
		for (j = 1 ; j <= n ; ++j)
		{
			if (!used[j] && dest[j] < MinPath)
			{
				iMinPath = j ;
				MinPath = dest[j] ;
			}
		}

		used[iMinPath] = true ;

		for (j = 1 ; j <= n ; ++j)
		{
			if (!used[j] && dest[iMinPath] + map[iMinPath][j] < dest[j])
				dest[j] = dest[iMinPath] + map[iMinPath][j] ;
		}
	}

	return dest[end] ;
}

int main (void)
{
	int i, j ;
	int x, y, c ;

	while (scanf ("%d%d", &n, &m), n | m)
	{
		memset (map, INF, sizeof (map)) ;
		for (i = 1 ; i <= m ; ++i)
		{
			scanf ("%d%d%d", &x, &y, &c) ;
			map[x][y] = map[y][x] = min (map[x][y], c) ;
		}

		printf ("%d\n", dijkstra (1, n)) ;
	}
	return 0 ;
}

 

 

Floyd 算法

/* THE PROGRAM IS MADE BY PYY */
/*----------------------------------------------------------------------------//
	Copyright (c) 2011 panyanyany All rights reserved.

	URL   : http://acm.hdu.edu.cn/showproblem.php?pid=2544
	Name  : 2544 最短路

	Date  : Thursday, January 5, 2012
	Time Stage : half an hour

	Result: 
5231253	2012-01-05 17:46:08	Accepted	2544
31MS	224K	1127 B
C++	pyy


Test Data :

Review :

//----------------------------------------------------------------------------*/

#include <stdio.h>
#include <string.h>

#define min(x, y)	((x) < (y) ? (x) : (y))
#define max(x, y)	((x) > (y) ? (x) : (y))

#define INF		0x3f3f3f3f
#define MAXN	102

int		n, m ;
int		map[MAXN][MAXN] ;

int floyd (const int start, const int end)
{
	int i, j, k ;

	for (k = 1 ; k <= n ; ++k)
		for (i = 1 ; i <= n ; ++i)
			for (j = 1 ; j <= n ; ++j)
				map[i][j] = min (map[i][j], map[i][k] + map[k][j]) ;

	return map[start][end] ;
}

int main (void)
{
	int i, j ;
	int x, y, c ;

	while (scanf ("%d%d", &n, &m), n | m)
	{
		memset (map, INF, sizeof (map)) ;
		for (i = 1 ; i <= m ; ++i)
		{
			scanf ("%d%d%d", &x, &y, &c) ;
			map[x][y] = map[y][x] = min (map[x][y], c) ;
		}

		printf ("%d\n", floyd (1, n)) ;
	}
	return 0 ;
}