2415. 反转二叉树的奇数层 --力扣 --JAVA

题目

解题思路

1. 奇数层，右子树的右子节点和左子树的左子节点交换，左子树的右子节点和右子树的左子节点交换。

代码展示

class Solution {
    public TreeNode reverseOddLevels(TreeNode root) {
        dfs(root.left,root.right,0);
        return root;
    }

    private void dfs(TreeNode left, TreeNode right, int index){
        if(left == null){
            return;
        }
        if(index % 2 == 0) {
            int temp = left.val;
            left.val = right.val;
            right.val = temp;
        }
        index++;
        dfs(left.left,right.right,index);
        dfs(left.right,right.left,index);
    }
}