5.1.3二叉树的后序遍历

文章目录

• ​​1.题目​​
• ​​2.代码​​

1.题目

• ​​题目要求​​
• 思路：后序遍历的顺序是左-右-根

2.代码

class Solution{
public:
  vector<int> postorderTraversal(TreeNode* root){
    vector<int> result;
    reverseFunction(root,result);
    return result;
  }
  
  void reverseFunction(TreeNode* node, vector<int>& tempvector){
    if (!node) return;
    if (node->left) reverseFunction(node->left, tempvector);
    if (node->right) reverseFunction(node->right, tempvector);
    tempvector.push_bakc(node->val);
  }
};

class Solution{
public:
  vector<int> postorderTraversal(TreeNode* root){
    vector<int> result;
    stack<TreeNode*> s;
    s.push(root);
    whiel (!s.empty())
    {
      TreeNode* node=s.top();
      s.pop();
      result.insert(result.begin(),s->val);
      if (root->left) s.push(root->left);
      if (root->right) s.push(root->right);
    }

    return result;
  }

};