MIT-Curricular/DS/C/Lab/Week12/BFS.c

93 lines
2.3 KiB
C

#include <stdio.h>
#include <stdlib.h>
#define MAX_VERTICES 100
typedef struct Node {
int vertex;
struct Node* next;
} Node;
typedef struct Graph {
int numVertices;
Node** adjLists;
} Graph;
typedef struct Queue {
int items[MAX_VERTICES];
int front, rear;
} Queue;
Graph* createGraph(int vertices) {
Graph* graph = malloc(sizeof(Graph));
graph->numVertices = vertices;
graph->adjLists = malloc(vertices * sizeof(Node*));
for (int i = 0; i < vertices; i++) graph->adjLists[i] = NULL;
return graph;
}
void addEdge(Graph* graph, int src, int dest) {
Node* newNode = malloc(sizeof(Node));
newNode->vertex = dest; newNode->next = graph->adjLists[src];
graph->adjLists[src] = newNode;
newNode = malloc(sizeof(Node));
newNode->vertex = src; newNode->next = graph->adjLists[dest];
graph->adjLists[dest] = newNode;
}
Queue* createQueue() {
Queue* queue = malloc(sizeof(Queue));
queue->front = queue->rear = -1;
return queue;
}
int isEmpty(Queue* queue) {
return queue->rear == -1;
}
void enqueue(Queue* queue, int value) {
if (queue->rear == MAX_VERTICES - 1) return;
if (queue->front == -1) queue->front = 0;
queue->items[++queue->rear] = value;
}
int dequeue(Queue* queue) {
if (isEmpty(queue)) return -1;
int item = queue->items[queue->front];
if (queue->front >= queue->rear) queue->front = queue->rear = -1;
else queue->front++;
return item;
}
void bfs(Graph* graph, int startVertex) {
int visited[MAX_VERTICES] = {0};
Queue* queue = createQueue();
visited[startVertex] = 1; enqueue(queue, startVertex);
while (!isEmpty(queue)) {
int currentVertex = dequeue(queue);
printf("%d ", currentVertex);
for (Node* temp = graph->adjLists[currentVertex]; temp; temp = temp->next) {
int adjVertex = temp->vertex;
if (!visited[adjVertex]) {
visited[adjVertex] = 1; enqueue(queue, adjVertex);
}
}
}
printf("\n");
}
int main() {
Graph* graph = createGraph(6);
addEdge(graph, 0, 1);
addEdge(graph, 0, 2);
addEdge(graph, 1, 3);
addEdge(graph, 1, 4);
addEdge(graph, 2, 5);
printf("BFS traversal starting from vertex 0:\n");
bfs(graph, 0);
return 0;
}