《剑指Offer》之“二叉搜索树的第k个结点”

题目描述

代码实现

class Solution {
public:
TreeNode* KthNode(TreeNode* pRoot, int k)
{
if(pRoot == nullptr || k < 0)
return nullptr;
stack<TreeNode*> s;
TreeNode *node = pRoot;
while(node != nullptr || !s.empty()){
if(node){
s.push(node);
node = node->left;
}
else{
node = s.top();
s.pop();
k--;
if(k == 0)
return node;
node = node->right;
}
}
return nullptr;
}

};