diff --git a/task01/src/com/example/task01/Task01Main.java b/task01/src/com/example/task01/Task01Main.java
index de4599c1..3feb6afb 100644
--- a/task01/src/com/example/task01/Task01Main.java
+++ b/task01/src/com/example/task01/Task01Main.java
@@ -23,7 +23,17 @@ public static <T, U> Function<T, U> ternaryOperator(
             Function<? super T, ? extends U> ifTrue,
             Function<? super T, ? extends U> ifFalse) {
 
-        return null; // your implementation here
+        if (condition == null || ifTrue == null || ifFalse == null) {
+            throw new NullPointerException();
+        }
+
+        return obj -> {
+            if (condition.test(obj)) {
+                return ifTrue.apply(obj);
+            } else {
+                return ifFalse.apply(obj);
+            }
+        };
 
     }
 }
diff --git a/task02/src/com/example/task02/Task02Main.java b/task02/src/com/example/task02/Task02Main.java
index 309260d8..421749ff 100644
--- a/task02/src/com/example/task02/Task02Main.java
+++ b/task02/src/com/example/task02/Task02Main.java
@@ -16,7 +16,13 @@ public static void main(String[] args) {
 
     public static IntStream cycleGrayCode(int n) {
 
-        return null; // your implementation here
+        if (n < 1 || n > 16) {
+            throw new IllegalArgumentException("Неверное значение \"n\". Значение должно быть от 1 до 16 включительно.");
+        }
+
+        int size = 1 << n;
+        return IntStream.iterate(0, i -> (i + 1) % size)
+                .map(i -> i ^ (i >> 1));
 
     }
 
diff --git a/task03/src/com/example/task03/Task03Main.java b/task03/src/com/example/task03/Task03Main.java
index 254d5cb0..2b444d49 100644
--- a/task03/src/com/example/task03/Task03Main.java
+++ b/task03/src/com/example/task03/Task03Main.java
@@ -2,7 +2,7 @@
 
 import java.util.Comparator;
 import java.util.function.BiConsumer;
-import java.util.stream.Stream;
+import java.util.stream.Stream;import java.util.Iterator;
 
 public class Task03Main {
 
@@ -22,6 +22,37 @@ public static <T> void findMinMax(
             Comparator<? super T> order,
             BiConsumer<? super T, ? super T> minMaxConsumer) {
 
-        // your implementation here
+        if (stream == null || order == null || minMaxConsumer == null) {
+            throw new NullPointerException();
+        }
+
+        Iterator<? extends T> iterator = stream.iterator();
+
+        if (!iterator.hasNext()) {
+            minMaxConsumer.accept(null, null);
+            return;
+        }
+
+        T min = null;
+        T max = null;
+
+
+        if (iterator.hasNext()) {
+            min = iterator.next();
+            max = iterator.next();
+
+            while (iterator.hasNext()) {
+                T element = iterator.next();
+
+                if (min == null || order.compare(element, min) < 0) {
+                    min = element;
+                }
+
+                if (max == null || order.compare(element, max) > 0) {
+                    max = element;
+                }
+            }
+        }
+        minMaxConsumer.accept(min, max);
     }
 }
diff --git a/task04/src/com/example/task04/Task04Main.java b/task04/src/com/example/task04/Task04Main.java
index 1e38e6eb..b5284be0 100644
--- a/task04/src/com/example/task04/Task04Main.java
+++ b/task04/src/com/example/task04/Task04Main.java
@@ -1,10 +1,26 @@
 package com.example.task04;
-
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.Collections;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 public class Task04Main {
 
     public static void main(String[] args) {
 
-        // your implementation here
+        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+        reader.lines()
+                .map(String::toLowerCase)
+                .flatMap(x -> Stream.of(x.split("[^a-zа-яё0-9]")))
+                .filter(x -> !x.isEmpty())
+                .collect(Collectors.groupingBy(x -> x, Collectors.counting()))
+                .entrySet()
+                .stream()
+                .sorted(Map.Entry.comparingByKey())
+                .sorted(Map.Entry.comparingByValue(Collections.reverseOrder()))
+                .limit(10)
+                .forEach(e -> System.out.print(e.getKey() + "\n"));
 
     }
 
diff --git a/task05/src/com/example/task05/IMail.java b/task05/src/com/example/task05/IMail.java
new file mode 100644
index 00000000..3d020d85
--- /dev/null
+++ b/task05/src/com/example/task05/IMail.java
@@ -0,0 +1,7 @@
+package com.example.task05;
+
+public interface IMail<T> {
+    String getFrom();
+    String getTo();
+    T getContent();
+}
diff --git a/task05/src/com/example/task05/MailMessage.java b/task05/src/com/example/task05/MailMessage.java
new file mode 100644
index 00000000..0a934c6b
--- /dev/null
+++ b/task05/src/com/example/task05/MailMessage.java
@@ -0,0 +1,25 @@
+package com.example.task05;
+
+public class MailMessage implements IMail<String> {
+    private String сontent;
+    private String to;
+    private String from;
+
+    public MailMessage(String from, String to, String Content) {
+        this.from = from;
+        this.to = to;
+        this.сontent = Content;
+    }
+
+    public String getContent() {
+        return сontent;
+    }
+
+    public String getTo() {
+        return to;
+    }
+
+    public String getFrom() {
+        return from;
+    }
+}
diff --git a/task05/src/com/example/task05/MailService.java b/task05/src/com/example/task05/MailService.java
new file mode 100644
index 00000000..decc15b7
--- /dev/null
+++ b/task05/src/com/example/task05/MailService.java
@@ -0,0 +1,26 @@
+package com.example.task05;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
+import java.util.Collections;
+
+public class MailService<T> implements Consumer<IMail<T>>{
+    private final Map<String, List<T>> mailBox = new HashMap<String, List<T>>() {
+        @Override
+        public List<T> get(Object key) {
+            return super.getOrDefault(key, Collections.emptyList());
+        }
+    };
+
+    @Override
+    public void accept(IMail<T> mail) {
+        mailBox.computeIfAbsent(mail.getTo(), k -> new ArrayList<>()).add(mail.getContent());
+    }
+
+    public Map<String, List<T>> getMailBox() {
+        return mailBox;
+    }
+}
diff --git a/task05/src/com/example/task05/Salary.java b/task05/src/com/example/task05/Salary.java
new file mode 100644
index 00000000..690012ef
--- /dev/null
+++ b/task05/src/com/example/task05/Salary.java
@@ -0,0 +1,25 @@
+package com.example.task05;
+
+public class Salary implements IMail<Integer> {
+    String companyName;
+    String to;
+    int salary;
+
+    Salary(String companyName, String name, int salary) {
+        this.companyName = companyName;
+        this.to = name;
+        this.salary = salary;
+    }
+
+    public String getFrom() {
+        return companyName;
+    }
+
+    public String getTo() {
+        return to;
+    }
+
+    public Integer getContent() {
+        return salary;
+    }
+}