杭电 hdu 1874 通畅工程续

杭电 hdu 1874 畅通工程续
第二次

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

	URL   : http://acm.hdu.edu.cn/showproblem.php?pid=1874
	Name  : 1874 畅通工程续
	Date  : Friday, August 19, 2011
	Time Stage : half an hour

	Result:
4453851	2011-08-19 21:39:38	Accepted	1874
31MS	4192K	1660 B
C++	pyy


	Test Data:

	Review:
那句相当重要的还是忘了，结果WA
//----------------------------------------*/

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

#define max(a, b) (((a) > (b)) ? (a) : (b))
#define min(a, b) (((a) < (b)) ? (a) : (b))

#define infinity    0x0f0f0f0f
#define minus_inf    0x80808080

#define MAXSIZE 1009

int city, road, start, end ;
int map[MAXSIZE][MAXSIZE], dp[MAXSIZE], used[MAXSIZE] ;

void dijkstra ()
{
	int i, j ;
	int iMinPath, minPath ;
	memset (used, 0, sizeof (used)) ;

	for (i = 0 ; i < city ; ++i)
		dp[i] = map[start][i] ;

	dp[start] = 0 ;	// 此句相当重要，不加则WA

	for (i = 0 ; i < city ; ++i)
	{
		minPath = infinity ;
		for (j = 0 ; j < city ; ++j)
		{
			if (!used[j] && dp[j] < minPath)
			{
				iMinPath = j ;
				minPath  = dp[j] ;
			}
		}
		used[iMinPath] = 1 ;
		for (j = 0 ; j < city ; ++j)
		{
			if (!used[j] && dp[iMinPath] + map[iMinPath][j] < dp[j])
				dp[j] = dp[iMinPath] + map[iMinPath][j] ;
		}
	}
}

int main ()
{
	int i ;
	int a, b, c ;
	while (scanf ("%d%d", &city, &road) != EOF)
	{
		memset (map, infinity, sizeof (map)) ;
		for (i = 0 ; i < road ; ++i)
		{
			scanf ("%d%d%d", &a, &b, &c) ;
			map[a][b] = map[b][a] = min (map[a][b], c) ;
		}
		scanf ("%d%d", &start, &end) ;
		dijkstra () ;
		if (dp[end] == infinity)
			printf ("-1\n") ;
		else
			printf ("%d\n", dp[end]) ;
	}
	return 0 ;
}

第一次

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

	URL   : http://acm.hdu.edu.cn/showproblem.php?pid=1874
	Name  : 1874 畅通工程续

	Date  : Saturday, May 14, 2011
	Time Stage : 1 hours around

	Result:
3953043	2011-05-14 10:57:25	Accepted	1874	15MS	460K	1462 B	C++	pyy
Test Data:

Review:
//----------------------------------------*/
#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
const int size = 210, infinite = 0x0f0f0f0f;
int city, path, from, to;
int dist[size], map[size][size], hash[size];

void dijkstra()
{
	int i, j, k;
	memset( hash, 0, sizeof(hash) );
	for( i = 0; i < city; ++i )
		dist[i] = map[i][to];
	hash[to] = 1;
	dist[to] = 0;	// 这句不加，就一直WA
	for( i = 0; i < city; ++i )
	{
		int minPath = infinite;
		int iMinPath = 0;
		for( j = 0; j < city; ++j )
			if( !hash[j] && dist[j] < minPath )
			{
				iMinPath = j;
				minPath = dist[j];
			}
		hash[iMinPath] = 1;
		for( j = 0; j < city; ++j )
			if( !hash[j] && dist[iMinPath] + map[iMinPath][j] < dist[j] )
				dist[j] = dist[iMinPath] + map[iMinPath][j];
	}
}

int main()
{
	int i, j, k, cost;
	while( cin >> city >> path )
	{
		memset( map, infinite, sizeof(map) );
		for( i = 0; i < path; ++i )
		{
			cin >> j >> k >> cost;
			map[j][k] = map[k][j] = min( map[j][k], cost );
		}
		cin >> from >> to;
		dijkstra();
		if( dist[from] == infinite )
			dist[from] = -1;
		cout << dist[from] << endl;
	}
	return 0;
}