226.invert-binary-tree.cpp

#include<iostream>
// #include<algorithm>
using namespace std;
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) {}
};
/*
 * @lc app=leetcode id=226 lang=cpp
 *
 * [226] Invert Binary Tree
 */

 // @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) {}
  * };
  */
class Solution {
public:
    void traverse(TreeNode* root) {
        if (!root)return;
        traverse(root->left);
        traverse(root->right);
        swap(root->left, root->right);
        return;
    }
    TreeNode* invertTree(TreeNode* root) {
        traverse(root);
        return root;
    }
};
// @lc code=end
int main() {
    TreeNode* root = new TreeNode(4, new TreeNode(2, new TreeNode(1), new TreeNode(3)), new TreeNode(7, new TreeNode(6), new TreeNode(9)));
    Solution s;
    s.invertTree(root);
    return 0;
}