diff --git a/Problem5.java b/Problem5.java
new file mode 100644
index 00000000..3839dcb9
--- /dev/null
+++ b/Problem5.java
@@ -0,0 +1,39 @@
+// Time Complexity : O(1)
+// Space Complexity : O(N)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+class MyHashMap {
+    int[] map;
+    boolean[] exists;
+
+    public MyHashMap() {
+        map = new int[1000001];
+        exists = new boolean[1000001];
+    }
+    
+    public void put(int key, int value) {
+        map[key] = value;
+        exists[key] = true;
+    }
+    
+    public int get(int key) {
+        if (exists[key]) {
+            return map[key];
+        }
+        return -1;
+        
+    }
+    
+    public void remove(int key) {
+        exists[key] = false;
+    }
+}
+
+/**
+ * Your MyHashMap object will be instantiated and called as such:
+ * MyHashMap obj = new MyHashMap();
+ * obj.put(key,value);
+ * int param_2 = obj.get(key);
+ * obj.remove(key);
+ */
\ No newline at end of file
diff --git a/Sample.java b/Sample.java
index 1739a9cb..6424f251 100644
--- a/Sample.java
+++ b/Sample.java
@@ -1,7 +1,48 @@
-// Time Complexity :
-// Space Complexity :
-// Did this code successfully run on Leetcode :
-// Any problem you faced while coding this :
+// Time Complexity : Amortized O(1)
+// Space Complexity : O(N)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+class MyQueue {
+    private Stack<Integer> in;
+    private Stack<Integer> out;
+
+    public MyQueue() {
+        this.in = new Stack<>();
+        this.out = new Stack<>();
+    }
+    
+    public void push(int x) {
+        in.push(x);
+    }
+    
+    public int pop() {
+        peek();
+        return out.pop();
+    }
+    
+    public int peek() {
+        if (out.isEmpty()) {
+            while(!in.isEmpty()) {
+                out.push(in.pop());
+            }
+        }
+        return out.peek();
+    }
+    
+    public boolean empty() {
+        return in.isEmpty() && out.isEmpty();
+    }
+}
+
+/**
+ * Your MyQueue object will be instantiated and called as such:
+ * MyQueue obj = new MyQueue();
+ * obj.push(x);
+ * int param_2 = obj.pop();
+ * int param_3 = obj.peek();
+ * boolean param_4 = obj.empty();
+ */
 
 
 // Your code here along with comments explaining your approach