added lost Strikeout file

.gitignore

@@ -1,5 +1,4 @@
 *.xml 
-java/out/
+java/out/*
 *.iml
 *.idea*
-*out*

java/markup/Strikeout.java

@@ -0,0 +1,24 @@
+package markup;
+
+import java.util.List;
+
+public class Strikeout extends AbstractMarkup {
+    public Strikeout(List<MarkupElement> elements) {
+        super(elements);
+    }
+
+    @Override
+    public void toMarkdown(StringBuilder sb) {
+        toMarkdown(sb, "~");
+    }
+
+    @Override
+    public void toHtml(StringBuilder sb) {
+        toHtml(sb, "s");
+    }
+
+    @Override
+    public void toTex(StringBuilder sb) {
+        toTex(sb, "\\textst");
+    }
+}

java/md2html/Md2Html.java

@@ -0,0 +1,146 @@
+package md2html;
+
+import java.io.*;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+
+public class Md2Html {
+
+    public static void main(String[] args) {
+        if (args == null || args.length < 2) {
+            return;
+        }
+
+        try (
+                BufferedReader reader = new BufferedReader(
+                        new InputStreamReader(new FileInputStream(args[0]), StandardCharsets.UTF_8));
+                BufferedWriter writer = new BufferedWriter(
+                        new OutputStreamWriter(new FileOutputStream(args[1]), StandardCharsets.UTF_8))
+        ) {
+            List<String> blocks = readBlocks(reader);
+            for (String block : blocks) {
+                writer.write(convertBlock(block));
+                writer.newLine();
+            }
+        } catch (IOException e) {
+            // по условию обычно можно игнорировать или просто завершить
+        }
+    }
+
+    private static List<String> readBlocks(BufferedReader reader) throws IOException {
+        List<String> blocks = new ArrayList<>();
+        StringBuilder current = new StringBuilder();
+        String line;
+
+        while ((line = reader.readLine()) != null) {
+            if (line.isEmpty()) {
+                if (!current.isEmpty()) {
+                    blocks.add(current.toString());
+                    current.setLength(0);
+                }
+            } else {
+                if (!current.isEmpty()) {
+                    current.append('\n');
+                }
+                current.append(line);
+            }
+        }
+
+        if (!current.isEmpty()) {
+            blocks.add(current.toString());
+        }
+
+        return blocks;
+    }
+
+    private static String convertBlock(String block) {
+        int level = countHeaderLevel(block);
+
+        if (level > 0) {
+            String content = block.substring(level + 1);
+            return "<h" + level + ">" + parseInline(content) + "</h" + level + ">";
+        } else {
+            return "<p>" + parseInline(block) + "</p>";
+        }
+    }
+
+    private static int countHeaderLevel(String block) {
+        int i = 0;
+        while (i < block.length() && block.charAt(i) == '#') {
+            i++;
+        }
+        if (i > 0 && i <= 6 && i < block.length() && block.charAt(i) == ' ') {
+            return i;
+        }
+        return 0;
+    }
+
+    private static String parseInline(String text) {
+        StringBuilder result = new StringBuilder();
+        Deque<String> stack = new ArrayDeque<>();
+
+        Map<String, String> tags = Map.of(
+                "*", "em",
+                "_", "em",
+                "**", "strong",
+                "__", "strong",
+                "--", "s",
+                "`", "code"
+        );
+
+        for (int i = 0; i < text.length(); ) {
+
+            // escape
+            if (text.charAt(i) == '\\' && i + 1 < text.length()) {
+                result.append(escapeHtml(text.charAt(i + 1)));
+                i += 2;
+                continue;
+            }
+
+            // check double markers first
+            if (i + 1 < text.length()) {
+                String two = text.substring(i, i + 2);
+                if (tags.containsKey(two)) {
+                    if (!stack.isEmpty() && stack.peek().equals(two)) {
+                        result.append("</").append(tags.get(two)).append(">");
+                        stack.pop();
+                    } else {
+                        result.append("<").append(tags.get(two)).append(">");
+                        stack.push(two);
+                    }
+                    i += 2;
+                    continue;
+                }
+            }
+
+            // single markers
+            String one = String.valueOf(text.charAt(i));
+            if (tags.containsKey(one)) {
+                if (!stack.isEmpty() && stack.peek().equals(one)) {
+                    result.append("</").append(tags.get(one)).append(">");
+                    stack.pop();
+                } else {
+                    result.append("<").append(tags.get(one)).append(">");
+                    stack.push(one);
+                }
+                i++;
+                continue;
+            }
+
+            // normal char
+            result.append(escapeHtml(text.charAt(i)));
+            i++;
+        }
+
+        return result.toString();
+    }
+
+    private static String escapeHtml(char c) {
+        return switch (c) {
+            case '<' -> "&lt;";
+            case '>' -> "&gt;";
+            case '&' -> "&amp;";
+            default -> String.valueOf(c);
+        };
+    }
+}