bfs.cpp

#include <iostream>
#include <algorithm>

int findCandidates(Graph* graph, int targetUser, int candidates[]) {
    Queue q;
    int visited[MAX_USERS] = {0};
    int distance[MAX_USERS] = {-1};
    int candidateCount = 0;
    
    // Initialize BFS
    enqueue(&q, targetUser, 0);
    visited[targetUser] = 1;
    distance[targetUser] = 0;
    
    while (!isEmpty(&q)) {
        Node current = dequeue(&q);
        // Explore neighbors (max 2 hops)
        if (current.distance < 2) {
            for (i = 0; i < graph->userCount; i++) {
                if (graph->adjMatrix[current.id][i] == 1 
                    && !visited[i]) {
                    visited[i] = 1;
                    distance[i] = current.distance + 1;
                    enqueue(&q, i, distance[i]);
                    
                    // Add 2-hop neighbors as candidates
                    if (distance[i] == 2) {
                        candidates[candidateCount++] = i;
                    }
                }
            }
        }
    }
    return candidateCount;
}