阅读量:0
Java中生成树形结构数据可以使用多种方法，下面列举了两种常用的方法：
方法一：使用递归实现
class TreeNode { int val; List<TreeNode> children; public TreeNode(int val) { this.val = val; this.children = new ArrayList<>(); } } public class TreeGenerator { public static TreeNode generateTree(int[] nums, int rootIndex) { if (rootIndex >= nums.length) { return null; } TreeNode root = new TreeNode(nums[rootIndex]); int leftChildIndex = 2 * rootIndex + 1; int rightChildIndex = 2 * rootIndex + 2; root.children.add(generateTree(nums, leftChildIndex)); root.children.add(generateTree(nums, rightChildIndex)); return root; } public static void main(String[] args) { int[] nums = {1, 2, 3, 4, 5, 6, 7}; TreeNode root = generateTree(nums, 0); // 打印树的结构 printTree(root, 0); } public static void printTree(TreeNode root, int level) { if (root == null) { return; } for (int i = 0; i < level; i++) { System.out.print("\t"); } System.out.println(root.val); for (TreeNode child : root.children) { printTree(child, level + 1); } } } 方法二：使用队列实现
class TreeNode { int val; List<TreeNode> children; public TreeNode(int val) { this.val = val; this.children = new ArrayList<>(); } } public class TreeGenerator { public static TreeNode generateTree(int[] nums) { if (nums.length == 0) { return null; } TreeNode root = new TreeNode(nums[0]); Queue<TreeNode> queue = new LinkedList<>(); queue.offer(root); int index = 1; while (!queue.isEmpty() && index < nums.length) { TreeNode currNode = queue.poll(); // 左孩子 if (index < nums.length) { TreeNode leftChild = new TreeNode(nums[index++]); currNode.children.add(leftChild); queue.offer(leftChild); } // 右孩子 if (index < nums.length) { TreeNode rightChild = new TreeNode(nums[index++]); currNode.children.add(rightChild); queue.offer(rightChild); } } return root; } public static void main(String[] args) { int[] nums = {1, 2, 3, 4, 5, 6, 7}; TreeNode root = generateTree(nums); // 打印树的结构 printTree(root, 0); } public static void printTree(TreeNode root, int level) { if (root == null) { return; } for (int i = 0; i < level; i++) { System.out.print("\t"); } System.out.println(root.val); for (TreeNode child : root.children) { printTree(child, level + 1); } } } 以上两种方法都可以根据给定的数组生成树形结构数据，并且可以通过递归或者队列的方式进行遍历和打印。
