너비 우선 탐색 (Breadth-First Search, BFS)

BFS(StartNode, GoalTest) {
    Create an empty FIFO Queue
    Create an empty Set Visited
    
    Enqueue(Queue, StartNode)
    Add(Visited, StartNode)
    
    while (Queue is not empty) {
        currentNode = Dequeue(Queue)
        
        if (GoalTest(currentNode) == TRUE) {
            return SolutionPath(currentNode)   // 최단 경로 반환
        }
        
        for each neighbor in Expand(currentNode) {
            if (neighbor not in Visited) {
                Add(Visited, neighbor)
                neighbor.parent = currentNode
                Enqueue(Queue, neighbor)
            }
        }
    }
    return FAILURE   // 해가 존재하지 않음
}