这道题用C++来写，在本地执行正常，但是使用OJ判断输出结果是空，暂时不清楚原因。代码如下：
class Solution { public: vector<int> V; //中序遍历 void MidTree(TreeNode node) { if (&node != NULL) { if (node.left != NULL) { MidTree(*node.left); } V.push_back(node.val); if (node.right != NULL) { MidTree(*node.right); } } } TreeNode Join(TreeNode* t, int ct) { if (ct == V.size() - 1) { TreeNode tt = TreeNode(V[ct]); return tt; } TreeNode d = TreeNode(V[ct + 1]); TreeNode* dd = &d; TreeNode n = Join(dd, ct + 1); t->right = &n; return *t; } TreeNode* increasingBST(TreeNode* root) { MidTree(*root); TreeNode T = TreeNode(V[0]); TreeNode* TT = &T; TreeNode x = Join(TT, 0); return &x; } };
保留原有逻辑，修改为C#代码，则通过所有测试，代码如下：
public class Solution { public List<int> V = new List<int>(); //中序遍历 public void MidTree(TreeNode node) { if (node != null) { if (node.left != null) { MidTree(node.left); } V.Add(node.val); if (node.right != null) { MidTree(node.right); } } } public TreeNode Join(TreeNode t, int ct) { if (ct == V.Count() - 1) { TreeNode tt =new TreeNode(V[ct]); return tt; } TreeNode d = new TreeNode(V[ct + 1]); TreeNode n = Join(d, ct + 1); t.right = n; return t; } public TreeNode IncreasingBST(TreeNode root) { MidTree(root); TreeNode T =new TreeNode(V[0]); TreeNode x = Join(T, 0); return x; } }
不知是leetcode的判断机制问题，还是我的C++写法的问题。之后还是尽量使用C#吧。
原文：https://www.cnblogs.com/asenyang/p/9721616.html