hdu2600java

好的，我明白了。针对你的问题，我猜测你是在问如何使用Java解决hdu1969这道题目。如果我的猜测正确，那么我可以给你一些思路和代码实现。 首先，我们需要明确题目的意思。题目要求我们求出一个多边形的面积，这个多边形由若干个点组成。我们可以使用海龙公式来计算多边形的面积，具体实现如下： ```java import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int n = scanner.nextInt(); while (n-- > 0) { int m = scanner.nextInt(); double x1 = scanner.nextDouble(); double y1 = scanner.nextDouble(); double x2 = scanner.nextDouble(); double y2 = scanner.nextDouble(); double x3 = scanner.nextDouble(); double y3 = scanner.nextDouble(); double a = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)); double b = Math.sqrt((x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3)); double c = Math.sqrt((x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3)); double p = (a + b + c) / 2; double s = Math.sqrt(p * (p - a) * (p - b) * (p - c)); System.out.printf("%.2f\n", s); } } } ``` 以上代码实现了对hdu1969题目的求解，你可以将其复制到你的Java IDE中进行编译和运行。

根据提供的引用内容，HDU1622是一道关于二叉树的题目，要求读入一系列二叉树的节点信息，输出它们的层序遍历结果。如果输入的二叉树不完整或存在重复节点，则输出"not complete"。下面是Java的实现代码： ```java import java.util.LinkedList; import java.util.Queue; import java.util.Scanner; public class Main { static class Node { int val; Node left, right; public Node(int val) { this.val = val; } } public static void main(String[] args) { Scanner sc = new Scanner(System.in); while (sc.hasNext()) { String s = sc.nextLine(); if (s.isEmpty()) { continue; } String[] nodes = s.split("\\s+"); Node root = new Node(Integer.parseInt(nodes[0].substring(1))); Queue<Node> queue = new LinkedList<>(); queue.offer(root); boolean isComplete = true; for (int i = 1; i < nodes.length - 1; i += 2) { Node cur = queue.poll(); if (!nodes[i].equals("()")) { cur.left = new Node(Integer.parseInt(nodes[i].substring(1))); queue.offer(cur.left); } else { isComplete = false; } if (!nodes[i + 1].equals("()")) { cur.right = new Node(Integer.parseInt(nodes[i + 1].substring(0, nodes[i + 1].length() - 1))); queue.offer(cur.right); } else { isComplete = false; } } if (!isComplete) { System.out.println("not complete"); continue; } StringBuilder sb = new StringBuilder(); queue.offer(root); while (!queue.isEmpty()) { Node cur = queue.poll(); sb.append(cur.val).append(" "); if (cur.left != null) { queue.offer(cur.left); } if (cur.right != null) { queue.offer(cur.right); } } System.out.println(sb.toString().trim()); } } } ```