upgrade to python3;add some validator examples

examples/StringFormatValidator.java

@@ -0,0 +1,69 @@
+/*
+ * 字符串格式验证程序
+ * 验证输出是否符合特定格式要求
+ * 编译: javac StringFormatValidator.java
+ * 使用: java StringFormatValidator input.txt expected.txt result.txt
+ */
+
+import java.io.*;
+import java.util.*;
+import java.util.regex.Pattern;
+
+public class StringFormatValidator {
+    public static void main(String[] args) {
+        if (args.length != 3) {
+            System.out.println("WA");
+            return;
+        }
+        
+        try {
+            // 读取期望的行数和格式信息
+            Scanner expected = new Scanner(new File(args[1]));
+            Scanner result = new Scanner(new File(args[2]));
+            
+            // 假设期望文件第一行是期望的行数
+            int expectedLines = expected.nextInt();
+            expected.nextLine(); // 消费换行符
+            
+            // 读取用户输出
+            List<String> userLines = new ArrayList<>();
+            while (result.hasNextLine()) {
+                String line = result.nextLine().trim();
+                if (!line.isEmpty()) {
+                    userLines.add(line);
+                }
+            }
+            
+            // 检查行数
+            if (userLines.size() != expectedLines) {
+                System.out.println("WA");
+                return;
+            }
+            
+            // 检查每行格式
+            boolean formatCorrect = true;
+            for (int i = 0; i < userLines.size(); i++) {
+                String line = userLines.get(i);
+                
+                // 检查是否符合 "Case #X: Y" 格式
+                Pattern pattern = Pattern.compile("^Case #" + (i + 1) + ": \\d+$");
+                if (!pattern.matcher(line).matches()) {
+                    formatCorrect = false;
+                    break;
+                }
+            }
+            
+            if (formatCorrect) {
+                System.out.println("AC");
+            } else {
+                System.out.println("PE"); // 格式错误
+            }
+            
+            expected.close();
+            result.close();
+            
+        } catch (Exception e) {
+            System.out.println("WA");
+        }
+    }
+}