/** * File: tree_node.dart * Created Time: 2023-2-12 * Author: Jefferson (JeffersonHuang77@gmail.com) */ /* 二叉树节点类 */ class TreeNode { int val; // 节点值 int height; // 节点高度 TreeNode? left; // 左子节点引用 TreeNode? right; // 右子节点引用 /* 构造方法 */ TreeNode(this.val, [this.height = 0, this.left, this.right]); } /* 将列表反序列化为二叉树:递归 */ TreeNode? listToTreeDFS(List arr, int i) { if (i < 0 || i >= arr.length || arr[i] == null) { return null; } TreeNode? root = TreeNode(arr[i]!); root.left = listToTreeDFS(arr, 2 * i + 1); root.right = listToTreeDFS(arr, 2 * i + 2); return root; } /* 将列表反序列化为二叉树 */ TreeNode? listToTree(List arr) { return listToTreeDFS(arr, 0); } /* 将二叉树序列化为列表:递归 */ void treeToListDFS(TreeNode? root, int i, List res) { if (root == null) return; while (i >= res.length) { res.add(null); } res[i] = root.val; treeToListDFS(root.left, 2 * i + 1, res); treeToListDFS(root.right, 2 * i + 2, res); } /* 将二叉树序列化为列表 */ List treeToList(TreeNode? root) { List res = []; treeToListDFS(root, 0, res); return res; }