Collection Tasks added

Collection Tasks/Word_Dictionary.java

@@ -0,0 +1,38 @@
+import java.util.*;
+
+public class Word_Dictionary {
+
+    public static void main(String[]args){
+        WordDictionary dict = new WordDictionary();
+        dict.addWord('a',"apple");
+        dict.addWord('a',"astronaut");
+        dict.addWord('b',"ball");
+        dict.addWord('c',"camera");
+        dict.addWord('d',"dress");
+        dict.printValues('a');
+        dict.printDictionay();
+    }
+
+    static class WordDictionary {
+        Map<Character,ArrayList<String>> word_dectionary;
+        public WordDictionary(){
+            word_dectionary = new HashMap<>();
+            for(char c='a';c<'z';c++){
+                word_dectionary.put(c,new ArrayList<>());
+            }
+        }
+        public void addWord(char key,String word){
+            word_dectionary.get(key).add(word);
+        }
+        public void printDictionay(){
+            for(Map.Entry m : word_dectionary.entrySet()){
+                System.out.println(m.getKey() + ": " + m.getValue());
+            }
+        }
+        public void printValues(char key){
+            System.out.println(word_dectionary.get(key));
+        }
+    }
+}
+
+

Collection Tasks/set.java

@@ -0,0 +1,69 @@
+import java.util.*;
+
+public class set {
+    public static void main(String[] args) {
+        Set_operations operations = new Set_operations();
+        Scanner scan = new Scanner(System.in);
+        int testNumber = scan.nextInt();
+
+        for (int i = 0; i < testNumber; i++) {
+
+            int number_of_operations = scan.nextInt();
+
+            for (int j = 0; j < number_of_operations; j++) {
+
+                String operation = scan.next();
+                int number;
+
+                switch (operation) {
+                    case "a":
+                        number = scan.nextInt();
+                        operations.addValue(number);
+                        break;
+
+                    case "b":
+                        operations.printSortedSet();
+                        break;
+
+                    case "c":
+                        number = scan.nextInt();
+                        operations.removeElement(number);
+                        break;
+
+                    case "d":
+                        number = scan.nextInt();
+                        operations.findNumber(number);
+                        break;
+
+                    case "e":
+                        operations.getSize();
+                        break;
+                }
+            }
+        }
+    }
+    static class Set_operations{
+        Set<Integer> operations;
+        public Set_operations(){
+            operations = new HashSet<>();
+        }
+        private void addValue(int number){
+            operations.add(number);
+        }
+        private void printSortedSet(){
+            List<Integer> sortedNumbers = new ArrayList<>(operations);
+            Collections.sort(sortedNumbers);
+            for (Integer n : sortedNumbers) System.out.print(n + " ");
+            System.out.println();
+        }
+        private void removeElement(int number){
+            operations.remove(number);
+        }
+        private void findNumber(int number){
+            System.out.println(operations.contains(number));
+        }
+        private void getSize(){
+            System.out.println(operations.size());
+        }
+    }
+}