c_cpp 从上往下打印二叉树的.cpp

Posted 2021-05-14

//从上往下打印出二叉树的每个节点，同层节点从左至右打印。




vector<int> PrintFromTopToBottom(TreeNode* pRoot) {
    vector<int> vecResult;
 
    if(NULL == pRoot)
    {
        return vecResult;
    }
    queue<TreeNode*> queTreeNode;
    queTreeNode.push(pRoot);
     
    TreeNode* temp;
    int iSize;
    while(!queTreeNode.empty() )
    {
        iSize = queTreeNode.size();
 
        temp = queTreeNode.front();
        vecResult.push_back( temp->val );
        if(NULL != temp->left)
        {
            queTreeNode.push( temp->left );
        }
        if(NULL != temp->right)
        {
            queTreeNode.push( temp->right );
        }
        queTreeNode.pop();
    }
    return vecResult;
}