Recover Binary Search Tree

最新推荐文章于 2022-03-13 20:36:15 发布

原创最新推荐文章于 2022-03-13 20:36:15 发布 · 612 阅读

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#中序遍历 #二叉树

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本文介绍了一种算法用于在不改变二叉搜索树结构的情况下修复两个元素位置错误的问题。通过使用栈来遍历树并记录前驱节点，找到需要交换的两个节点后进行位置调整。

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Two elements of a binary search tree (BST) are swapped by mistake.

Recover the tree without changing its structure.

#include<iostream>
#include<vector>
#include<stack>
using namespace std;

struct TreeNode {
	int val;
	TreeNode *left;
	TreeNode *right;
	TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};


void recoverTree(TreeNode *root) {

	TreeNode* pre_node = NULL;
	stack<TreeNode*>StackNode;
	TreeNode*cur_node = root;
	TreeNode*misnode1 = NULL;
	TreeNode*misnode2 = NULL;
	while (1)
	{
		while (cur_node)
		{
			StackNode.push(cur_node);
			cur_node = cur_node->left;
		}
		if (StackNode.empty())  
			break; 
		cur_node = StackNode.top();
		StackNode.pop();
		if (pre_node!=NULL&&pre_node->val>cur_node->val)
		{
			if (!misnode1){
				misnode1 = pre_node;
				misnode2 = cur_node;
			}
			else
				misnode2 = cur_node;
		}
		pre_node = cur_node;
		cur_node = cur_node->right;
	}
    if (misnode1&&misnode2)
		swap(misnode1->val,misnode2->val);
}