Added 17 solutions

Java/Data Structures/Java Dequeue/Solution.java

@@ -11,33 +11,23 @@ import java.util.HashMap;
 // O(n) space complexity
 public class test {
     public static void main(String[] args) {
-        /* Create our data structures */
-        Deque<Integer> deque = new ArrayDeque<>();
         HashMap<Integer, Integer> map = new HashMap<>();
+        Deque<Integer> deque          = new ArrayDeque<>();
         
-        /* Save first m entries */
         Scanner scan = new Scanner(System.in);
         int n = scan.nextInt();
-        int m = scan.nextInt();
-        for (int i = 0; i < m; i++) {
-            int num = scan.nextInt();
-            deque.add(num);
-            if (map.containsKey(num)) {
-                map.put(num, map.get(num) + 1);
-            } else {
-                map.put(num, 1);
-            }
-        }
-        
-        /* Loop through remaining n-m entries */
+        int m = scan.nextInt();        
         int max = map.size();
-        for (int i = m; i < n; i++) {
-            /* Remove old value */
-            int old = deque.remove();
-            if (map.get(old) == 1) {
-                map.remove(old);
-            } else {
-                map.put(old, map.get(old) - 1);
+        
+        for (int i = 0; i < n; i++) {
+            /* Remove old value (if necessary) */
+            if (i >= m) {
+                int old = deque.remove();
+                if (map.get(old) == 1) {
+                    map.remove(old);
+                } else {
+                    map.put(old, map.get(old) - 1);
+                }
             }
             /* Add new value */
             int num = scan.nextInt();
@@ -50,6 +40,8 @@ public class test {
             
             max = Math.max(max, map.size());
         }
+        
+        scan.close();
         System.out.println(max);
     }
 }