public class InvertTree_226 {

class TreeNode {

int val;

TreeNode left;

TreeNode right;

TreeNode() {

}

TreeNode(int val) {

this.val = val;

}

TreeNode(int val, TreeNode left, TreeNode right) {

this.val = val;

this.left = left;

this.right = right;

}

}

/**

* 使用递归的方法求解

* @param root

* @return

*/

public TreeNode invertTree(TreeNode root) {

// 递归终止逻辑

if (root == null) {

return null;

}

// 当前层递归逻辑

TreeNode node = root.left;

root.left = root.right;

root.right = node;

// 下探到下一层

invertTree(root.left);

invertTree(root.right);

return root;

}

}