https://leetcode.com/problems/binary-tree-pruning/ 1. 2022.02.05 시도 소요시간: 5분 // dfs class Solution { public TreeNode pruneTree(TreeNode root) { root = dfs(root); return root; } public TreeNode dfs(TreeNode root) { if (root == null) { return null; } TreeNode left = dfs(root.left); if (left == null) { root.left = null; } TreeNode right = dfs(root.right); if (right == null) { root.right = null; } i..