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Copy path114.flatten-binary-tree-to-linked-list.cpp
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114.flatten-binary-tree-to-linked-list.cpp
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/*
* @lc app=leetcode id=114 lang=cpp
*
* [114] Flatten Binary Tree to Linked List
*/
// @lc code=start
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
#include <algorithm>
#include <iostream>
#include <memory.h>
#include <stack>
#include <unordered_map>
#include <utility>
#include <vector>
using namespace std;
class Solution {
public:
TreeNode* visit(TreeNode* root) {
if (root == nullptr) {
return nullptr;
}
if (root->left == nullptr && root->right == nullptr) {
return root;
}
TreeNode* left = visit(root->left);
TreeNode* right = visit(root->right);
if (left != nullptr) {
left->right = root->right;
root->right = root->left;
root->left = nullptr;
}
return right == nullptr ? left : right;
}
void flatten(TreeNode* root) {
visit(root);
}
};
// @lc code=end