leetcode/java/226_Invert_Binary_Tree.java at master · cphysics/leetcode

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https://leetcode.com/problems/invert-binary-tree/

Invert a binary tree.

Invert left and right subtrees then swap.

Time - O(n)

Space - O(1)

/**

* Definition for a binary tree node.

public class TreeNode {

int val;

TreeNode left;

TreeNode right;

TreeNode(int x) { val = x; }

}

public class Solution {

public TreeNode invertTree(TreeNode root) {

if (root == null)

return null;

TreeNode left = invertTree(root.left);

TreeNode right = invertTree(root.right);

root.left = right;

root.right = left;

return root;

}