2叉搜索树层级遍历

可以用队列,也可以用数组的方式实现.这里我图方便,用的数组

void printNode(treeNode* rootNode) {//当前设置最多打印5层
	 if (!rootNode)return;
	 treeNode** fatherArr = new treeNode * [128]{};//每打印完一个父亲数组换行,子数*2,为空的位置也打印出来
	 treeNode** sonArr = new treeNode * [128]{};
	 cout << "-----------" << rootNode->data << "-----------" << endl;
	 if (rootNode->left_son) {
		 fatherArr[0] = rootNode->left_son;
	 }if (rootNode->right_son) {
		 fatherArr[1] = rootNode->right_son;
	 }
	 if (rootNode->left_son == nullptr && rootNode->right_son == nullptr)return;
	 size_t sonCountMax = 4;
	 size_t fatherCount = 2;
	 /*for (size_t i = 0; i < 2; ++i) {
		 if (fatherArr[i]) {
			 cout << fatherArr[i]->data << "\t";
		 }
		 else {
			 cout << "空\t";
		 }
	 }*/
	 int reverse = 0; size_t nullCount = 0;
	 size_t sonArrcount = 0;
	 while (true) {
		  sonArrcount = 0;		  
		 //不是最后一层,father<->son,儿子数组元素分裂儿子到父亲数组(每一次反转)相互转化			  
			  nullCount = 0;
			  
			  if (reverse%2) {
				  for (size_t i = 0; i < fatherCount; ++i) {
					  if (sonArr[i]) {
						  cout << sonArr[i]->data << "\t";
						  if (sonArr[i]->left_son) {
							  fatherArr[sonArrcount] = sonArr[i]->left_son;
						  }
						  else {
							  fatherArr[sonArrcount] = nullptr;
						  }
						  ++sonArrcount;
						  if (sonArr[i]->right_son) {
							  fatherArr[sonArrcount] = sonArr[i]->right_son;
						  }
						  else {
							  fatherArr[sonArrcount] = nullptr;
						  }
						  ++sonArrcount;
					  }
					  else {
						  cout << " - ";
						  fatherArr[sonArrcount] = nullptr;
						  ++sonArrcount;
						  fatherArr[sonArrcount] = nullptr;
						  ++sonArrcount;
					  }
				  }
				  for (size_t i = 0; i < sonCountMax; ++i) {
					  if (fatherArr[i] == nullptr) {
						  ++nullCount;
					  }
				  }
			  }
			  else {				  
				  for (size_t i = 0; i < fatherCount; ++i) {
					  if (fatherArr[i]) {
						  cout << fatherArr[i]->data << "\t";
						  if (fatherArr[i]->left_son) {
							  sonArr[sonArrcount] = fatherArr[i]->left_son;
						  }
						  else {
							  sonArr[sonArrcount] = nullptr;
						  }
						++sonArrcount;
						if (fatherArr[i]->right_son) {
							sonArr[sonArrcount] = fatherArr[i]->right_son;
						}
						else {
							sonArr[sonArrcount] = nullptr;
						}
						++sonArrcount;
					  }
					  else {
						  cout << " - ";
						  sonArr[sonArrcount] = nullptr;
						  ++sonArrcount;
						  sonArr[sonArrcount] = nullptr;
						  ++sonArrcount;
					  }
				  }for (size_t i = 0; i < sonCountMax; ++i) {
					  if (sonArr[i] == nullptr) {
						  ++nullCount;
					  }
				  }
			  }++reverse;
			  cout << endl;
			  if (nullCount == sonCountMax) {
				  cout << "已是最后一层" << endl;
				  return;
			  }
			  if (sonCountMax>=128||fatherCount>=128) {
				  cout << "已超出打印层数限制" << endl;
				  return;
			  }
			  else {
				  sonCountMax = sonCountMax << 1;
				  fatherCount = fatherCount << 1;
			  }
	 }
 }

 

 

来源：CSDN

作者：贰月红

链接：https://blog.csdn.net/weixin_37520565/article/details/104614616