题解 | #二叉树的镜像#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param pRoot TreeNode类
     * @return TreeNode类
     */

    public TreeNode Mirror (TreeNode pRoot) {
        // write code here
        if (pRoot == null) {
            return null;
        }
        Queue<TreeNode> queue = new LinkedList<>();
        queue.add(pRoot);
        while (!queue.isEmpty()) {
            TreeNode temp = queue.poll();
            if (temp.left != null) {
                queue.add(temp.left);
            }
            if (temp.right != null) {
                queue.add(temp.right);
            }
            TreeNode s = temp.left;
            temp.left = temp.right;
            temp.right = s;
        }
        return pRoot;
    }
}