c语言公交最优路径查询数据结构,c语言公交最优路径查询数据结构(附完整代码)
时间: 2023-10-07 21:11:25 浏览: 52
该问题可以使用Dijkstra算法来解决,Dijkstra算法是一种贪心算法,用于解决带有非负权重的图的单源最短路径问题。
首先,我们需要定义一个结构体来表示每个节点:
```c
typedef struct {
int vertex;
int weight;
} Edge;
typedef struct {
int vertex;
int distance;
int predecessor;
int visited;
Edge edges[MAX_EDGES];
int edge_count;
} Node;
```
其中,`vertex`表示节点的编号,`distance`表示从起点到该节点的最短距离,`predecessor`表示从起点到该节点的最短路径上该节点的前一个节点,`visited`表示该节点是否已经被访问过,`edges`表示该节点与其他节点之间的边,`edge_count`表示该节点有多少个邻居节点。
然后,我们需要构建图。这里我们假设所有节点之间的边都是双向的,即如果节点A到节点B有一条边,那么节点B到节点A也有一条边。我们将图表示为一个节点数组,每个节点包含了它与其他节点之间的边。
```c
Node graph[MAX_NODES];
int node_count = 0;
void add_edge(int from, int to, int weight) {
graph[from].edges[graph[from].edge_count].vertex = to;
graph[from].edges[graph[from].edge_count].weight = weight;
graph[from].edge_count++;
}
```
接下来,我们需要实现Dijkstra算法。我们用一个堆来存储所有未访问过的节点,每次从堆中取出距离起点最近的节点进行处理,然后将该节点的邻居节点加入堆中。
```c
int heap[MAX_NODES];
int heap_count = 0;
void heap_push(int vertex) {
heap[heap_count] = vertex;
int child = heap_count;
int parent = (child - 1) / 2;
while (child > 0 && graph[heap[parent]].distance > graph[vertex].distance) {
heap[child] = heap[parent];
child = parent;
parent = (child - 1) / 2;
}
heap[child] = vertex;
heap_count++;
}
int heap_pop() {
int vertex = heap[0];
heap_count--;
heap[0] = heap[heap_count];
int parent = 0;
int child = 1;
while (child < heap_count) {
if (child + 1 < heap_count && graph[heap[child + 1]].distance < graph[heap[child]].distance) {
child++;
}
if (graph[heap[parent]].distance <= graph[heap[child]].distance) {
break;
}
int temp = heap[parent];
heap[parent] = heap[child];
heap[child] = temp;
parent = child;
child = parent * 2 + 1;
}
return vertex;
}
void dijkstra(int start) {
for (int i = 0; i < node_count; i++) {
graph[i].distance = INT_MAX;
graph[i].visited = 0;
graph[i].predecessor = -1;
}
graph[start].distance = 0;
heap_push(start);
while (heap_count > 0) {
int vertex = heap_pop();
if (graph[vertex].visited) {
continue;
}
graph[vertex].visited = 1;
for (int i = 0; i < graph[vertex].edge_count; i++) {
int neighbor = graph[vertex].edges[i].vertex;
if (!graph[neighbor].visited) {
int distance = graph[vertex].distance + graph[vertex].edges[i].weight;
if (distance < graph[neighbor].distance) {
graph[neighbor].distance = distance;
graph[neighbor].predecessor = vertex;
heap_push(neighbor);
}
}
}
}
}
```
最后,我们可以通过调用`dijkstra`函数来求出最短路径。在该函数返回后,每个节点的`distance`字段将包含从起点到该节点的最短距离,`predecessor`字段将包含从起点到该节点的最短路径上该节点的前一个节点。
完整代码如下: