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

//代码：

//方法1：Dijkstra's Algorithm

#include<stdio.h>
#include<math.h>
#include<string.h>
#define INF 0xfffffff
#define N 110
#define min(a, b)(a < b ? a : b)

int maps[N][N];
int d[N], visit[N];
int n, m;

void Init()
{
    int i, j;
    memset(visit, , sizeof(visit));
    for(i =  ; i <= n ; i++)
    {
        d[i] = INF;
        for(j =  ; j <= n ; j++)
            maps[i][j] = INF;
    }
}

void Dij()
{
    int i, j, x, min;
    d[] = ;
    for(i =  ; i <= n ; i++)
    {
        min = INF;
        for(j =  ; j <= n ; j++)
        {
            if(!visit[j] && d[j] < min)
            {
                min = d[j];
                x = j;
            }
        }
        visit[x] = ;
        for(j =  ; j <= n ; j++)
        {
            if(!visit[j] && d[j] > d[x] + maps[x][j])
                d[j] = d[x] + maps[x][j];
        }
    }
}

int main()
{
    int i, a, b, c;
    while(scanf("%d%d", &n, &m), m + n != )
    {
        Init();
        for(i =  ; i <= m ; i++)
        {
            scanf("%d%d%d", &a, &b, &c);
            maps[a][b] = min(maps[a][b], c);
            maps[b][a] = maps[a][b];
        }
        Dij();
        printf("%d\n", d[n]);
    }
    return ;
}//单元最短路

//方法2：弗洛伊德算法

#include<stdio.h>
#include<string.h>
#define N 110
#define INF 0xfffffff
#define min(a, b) (a < b ? a : b)

int maps[N][N];
int n, m;

void Init()
{
    int i, j;
    for(i =  ; i <= n ; i++)
        for(j =  ; j <= n ; j++)
            maps[i][j] = INF;
}

void Floyd()
{
    int i, k, j;
    for(k =  ; k <= n ; k++)
    {
        for(i =  ; i <= n ; i++)
        {
            for(j =  ; j <= n ; j++)
                maps[i][j] = min(maps[i][j], maps[i][k] + maps[k][j]);
        }
    }
}

int main()
{
    int a, b, c, i;
    while(scanf("%d%d", &n, &m), m + n != )
    {
        Init();
        for(i =  ; i <= m ; i++)
        {
            scanf("%d%d%d", &a, &b, &c);
            maps[a][b] = min(maps[a][b], c);
            maps[b][a] = maps[a][b];
        }
        Floyd();
        printf("%d\n", maps[][n]);
    }
    return ;
}//多元最短路