HDOJ 2544 Dijkstra

迪杰斯特拉算法的过程如下：

初始化，把除起点之外的所有点到起点的距离初始化为 INF，起点到起点的距离记为0，标记清空，；

FOR i = 1:n

　　选取到起点距离最近的结点；

　　如果选取的点为目标点，结束，否则标记这个点，并对它相邻的所有点进行松弛操作；

END

-----------------------------------------------------------------------------------

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

# define N 105
# define INF 100005

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

int min(int x, int y)
{
    return (x<y ? x:y);
}

void init(void)
{
    int i, j, u, v, t;
    
    for (i = 1; i <= n; ++i)
    for (j = 1; j <= n; ++j)
    {
        w[i][j] = INF;
    }

    for (i = 0; i < m; ++i)
    {
        scanf("%d%d%d", &u, &v, &t);
        if (t < w[u][v]) w[u][v] = w[v][u] = t;
    }
}

void solve(void)
{
    int d[N], i, m, x, j;
    char v[N];
    
    memset(v, 0, sizeof(v));
    for (d[1] = 0, i = 2; i <= n; ++i)
        d[i] = INF;
    for (i = 1; i <= n; ++i)
    {
        m = INF;
        for (j = 1; j <= n; ++j) if (!v[j] && d[j]<=m) m = d[x = j];
        if (x == n) break;
        v[x] = 1;
        for (j = 1; j <= n; ++j) d[j] = min(d[j], d[x]+w[x][j]);
    }
    printf("%d\n", d[n]);
}

int main()
{    
    while (scanf("%d%d", &n, &m), n&&m)
    {
        init();
        solve();
    }

    return 0;
}

------------------------------------------------------------------------------