題目描述
操作給定的二叉樹，將其變換為源二叉樹的鏡像。

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public void Mirror(TreeNode root) {
        if(root==null) return;
        TreeNode left = root.left;
        TreeNode right = root.right;
        root.left = right;
        root.right = left;
        Mirror(left);
        Mirror(right);
    }
    
}