LeetCode 专用 Java 模板，只保留刷题最常用的打印代码

› LeetCode 专用 Java 模板只保留刷题最常用的打印代码• import java.util.*;public class Main {static class ListNode {int val;ListNode next;ListNode(int val) { this.val val; }}static class TreeNode {int val;TreeNode left, right;TreeNode(int val) { this.val val; }}public static void main(String[] args) {// 1. 一维数组int[] arr {1, 2, 3, 4};System.out.println(Arrays.toString(arr));// 2. 二维数组int[][] grid {{1, 2}, {3, 4}};System.out.println(Arrays.deepToString(grid));// 3. ListListInteger list Arrays.asList(1, 2, 3);System.out.println(list);// 4. MapMapString, Integer map new HashMap();map.put(a, 1);map.put(b, 2);System.out.println(map);// 5. 链表ListNode head new ListNode(1);head.next new ListNode(2);head.next.next new ListNode(3);printList(head);// 6. 二叉树TreeNode root new TreeNode(1);root.left new TreeNode(2);root.right new TreeNode(3);root.left.right new TreeNode(4);preorder(root);System.out.println();levelOrder(root);System.out.println();}// 打印链表: 1 - 2 - 3static void printList(ListNode head) {while (head ! null) {System.out.print(head.val);if (head.next ! null) System.out.print( - );head head.next;}System.out.println();}// 前序打印二叉树static void preorder(TreeNode root) {if (root null) return;System.out.print(root.val );preorder(root.left);preorder(root.right);}// 层序打印二叉树static void levelOrder(TreeNode root) {if (root null) return;QueueTreeNode queue new LinkedList();queue.offer(root);while (!queue.isEmpty()) {TreeNode node queue.poll();System.out.print(node.val );if (node.left ! null) queue.offer(node.left);if (node.right ! null) queue.offer(node.right);}}}最常用就记这几个System.out.println(Arrays.toString(arr));System.out.println(Arrays.deepToString(grid));System.out.println(list);System.out.println(map));printList(head);preorder(root);levelOrder(root);注意这里有个常见笔误map 那行正确写法是System.out.println(map);