Question

对于学校项目，我必须修改教授给出的Dijkstra短路径代码，并将优先级队列从简单数组更改为堆。这个想法很清楚但我无法理解我应该在堆节点中包含什么，因为在代码中我有3个不同的数组，一个用于两个节点之间的距离，一个用于节点的前驱，一个用于布尔如果我还没有访问过节点那就说

int *Dijkstra(int s, int n) //restituisce array dei predecessori
{
    //S nodi gia' visitati, Q nodi ancora da visitare
    int u, v, nVisited;
    int *d, *p; //array, distanze e pred dei nodi
    bool *Q; //coda di priorita' con array
    Vertex *vnext;
    d = (int*)malloc(n* sizeof(int));
    p = (int*)malloc(n* sizeof(int));
    Q = (bool*)malloc(n* sizeof(bool));
    for (v = 0; v<n; v++)
    {
        d[v] = INT_MAX;
        p[v] = -1;
        Q[v] = true;
    }
    d[s] = 0;
    p[s] = s;
    nVisited = 0;
    while (nVisited < n)
    {
        u = extractMin(Q, d, n);
        nVisited++;
        Q[u] = false; //non e' più da visitare
        vnext = Adj[u];
        while (vnext!= NULL)
        {
            v = vnext->id;
            if ((d[v] > d[u] + vnext->dist))
            {
                d[v] = d[u] + vnext->dist;
                p[v] = u;
            }
            vnext = vnext->next;
        }
    }
    return p;
}

Vertex的位置：

typedef struct _Vertex
{
    int id;
    int dist;
    struct _Vertex* next;
} Vertex;
Vertex** Adj;

Adj数组通过正确创建它的readfile进行初始化。

我对堆的想法是：

typedef struct node {
    //What should I put here?
    //I thought about int distance, predecessors;
} node ;

typedef struct minHeap {
    int size ;
    node *elem ;
} minHeap ;

C，Dijkstra堆优先级队列实现

0 个答案: