【C语言/数据结构】二叉树（层序遍历|判断完全二叉树|性质）

//初始化
void QueueInit(Queue* pq)
{
	assert(pq);
	pq->phead = pq->ptail = NULL;
	pq->size = 0;
}

//销毁
void QueueDestroy(Queue* pq)
{
	assert(pq);
	QNode* cur = pq->phead;
	while (cur)
	{
		QNode* next = cur->next;
		free(cur);
		cur = next;
	}
	pq->phead = pq->ptail = NULL;
	pq->size = 0;
}

//插入
void QueuePush(Queue* pq, QDataType x)
{
	assert(pq);
	QNode* newnode = (QNode*)malloc(sizeof(QNode));
	if (newnode == NULL)
	{
		perror("malloc fail");
		return;
	}
	newnode->val = x;
	newnode->next = NULL;

	if (pq->ptail == NULL)
	{
		pq->ptail = pq->phead = newnode;
	}
	else
	{
		pq->ptail->next = newnode;
		pq->ptail = newnode;
	}
	pq->size++;
}

//删除
void QueuePop(Queue* pq) 
{
	assert(pq);
	assert(pq->phead);

	QNode* del = pq->phead;
	pq->phead = pq->phead->next;
	free(del);
	del = NULL;
	if (pq->phead == NULL)
	{
		pq->ptail = NULL;	
	}
	pq->size--;
}

//取队头
QDataType QueueFront(Queue* pq)
{
	assert(pq);
	assert(pq->phead);
	return pq->phead->val;
}


 //判断是否为空
bool QueueEmpty(Queue* pq)
{
	assert(pq);
	return pq->phead == NULL;
}

//节点个数
int	QueueSize(Queue* pq)
{
	assert(pq);
	return pq->size;
}

typedef struct BinaryTreeNode* QDataType;
typedef struct QueueNode
{	
	QDataType val;
	struct QueueNode* next;
}QNode;

typedef struct Queue
{
	QNode* phead;
	QNode* ptail;
	int size;
}Queue;

// 层序遍历
void BinaryTreeLevelOrder(BTNode* root)
{
	Queue q;
	QueueInit(&q);
	if (root)
		QueuePush(&q, root);

	int levelSize = 1;
	while (!QueueEmpty(&q))
	{
		// 一层一层出
		while (levelSize--)
		{
			BTNode* front = QueueFront(&q);
			QueuePop(&q);

			printf("%d ", front->data);

			if (front->left)
				QueuePush(&q, front->left);

			if (front->right)
				QueuePush(&q, front->right);
		}
		printf("\n");

		levelSize = QueueSize(&q);
	}
	printf("\n");

	QueueDestroy(&q);
}

// 判断二叉树是否是完全二叉树
bool BinaryTreeComplete(BTNode* root)
{
	Queue q;
	QueueInit(&q);
	if (root)
		QueuePush(&q, root);

	int levelSize = 1;
	while (!QueueEmpty(&q))
	{
		BTNode* front = QueueFront(&q);
		QueuePop(&q); 

		if (front == NULL)
			break;

		QueuePush(&q, front->left);
		QueuePush(&q, front->right);
	}

	// 前面遇到空以后，后面还有非空就不是完全二叉树
	while (!QueueEmpty(&q))
	{
		BTNode* front = QueueFront(&q);
		QueuePop(&q);

		if (front)
		{
			QueueDestroy(&q);
			return false;
		}
	}

	QueueDestroy(&q);
	return true;
}