题目226. Invert Binary Tree
Invert a binary tree.
4
/
2 7
/ \ /
1 3 6 9
to
4
/
7 2
/ \ /
9 6 3 1
Trivia:
This problem was inspired by this original tweet by Max Howell:
Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.
1,递归
思路:递归的交换左右子树
public class Solution {
public TreeNode invertTree(TreeNode root) {
dfs(root);
return root;
}
private void dfs(TreeNode root){
if(root == null){
return;
}
TreeNode temp = root.left;
root.left = root.right;
root.right = temp;
dfs(root.left);
dfs(root.right);
}
}
