dijkstra算法 模板

算法理解见： https://www.bilibili.com/video/av18586085/?p=83

模板:

#define INF 1000000000

int N;
int dist[101], g[101][101];
int vis[101];
int path[101];    // path[i]表示在最短路径中，i的上一个点

void init()       // 初始化
{
    for (int i = 1; i <= N; ++i)
    {
        for (int j = 1; j <= N; ++j)
        {
            if (i == j)
                g[i][j] = 0;
            else
                g[i][j] = INF;
        }
    }
}

void dijkstra(int start)
{
    for(int i = 0; i <= N; ++i)
    {
        dist[i] = INF;
        vis[i] = 0;
        path[i] = -1;
    }
    dist[start] = 0;

    while (1)
    {
        int mark = -1, mindis = INF;
        for (int i = 1; i <= N; i++)
        {
            if (!vis[i] && dist[i] < mindis)
            {
                mindis = dist[i];
                mark = i;
            }
        }
        if (mark == -1)    // 找不到未收录的节点，则说明算法结束，退出
            break;
        vis[mark] = 1;

        for (int i = 1; i <= N; i++)
        {
            if(!vis[i] && dist[mark] + g[mark][i] < dist[i])
            {
                dist[i] = dist[mark] + g[mark][i];
                path[i] = mark;    // 记录路径
            }
        }
    }

    // 逆序打印路径
    int k = Sp;        //假设终点是Sp
    while(k != -1)
    {
        printf("%d ", k);
        k = path[k];
    }
    printf("%d", start);
}