Design-2

HashMap.java

@@ -0,0 +1,78 @@
+class MyHashMap {
+
+    class Node {
+     int key;
+     int value;
+     Node next;
+     public Node(int key, int value){
+        this.key=key;
+        this.value=value;
+     }
+  } 
+     Node[] s;
+     int bucket=10000;
+    public MyHashMap() {
+
+        this.bucket=10000;
+        this.s=new Node[bucket]; 
+    }
+    int getHash(int key){
+        return key % bucket;
+    }
+    Node getPrev(Node head, int key){
+        Node prev=null;
+        Node curr=head;
+        if(curr!=null && curr.key!=key){
+            prev=curr;
+            curr=curr.next;
+        }
+        return prev;
+    }
+    public void put(int key, int value) {
+        int idx=getHash(key);
+        if(s[idx]==null)
+           s[idx]=new Node(-1,-1);
+        Node prev=getPrev(s[idx],key);
+        if(prev.next==null)
+            prev.next= new Node(key,value);
+        else{
+            prev.next.value=value;
+        }
+    }
+
+    public int get(int key) {
+        int idx=getHash(key);
+        if(s[idx]==null){
+           return -1;
+        }
+        Node prev=getPrev(s[idx],key);
+        if(prev.next==null){
+            return -1;
+        }
+
+          return prev.next.value;
+    }
+
+    public void remove(int key) {
+        int idx=getHash(key);
+        if(s[idx]==null){
+          return;
+        }
+        Node prev=getPrev(s[idx],key);
+        if(prev.next==null){
+          return;
+        }
+        Node cur=prev.next;
+        prev.next=cur.next;
+        cur=null;
+
+    }
+}
+
+/**
+ * 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);
+ */

QueueAsStack.java

@@ -0,0 +1,46 @@
+class MyQueue {
+    Stack<Integer> in;
+    Stack<Integer> out;
+    public MyQueue() {
+        this.in= new Stack<>();
+         this.out= new Stack<>();
+    }
+
+    public void push(int x) {
+        in.push(x);
+    }
+
+    public int pop() {
+        if(out.isEmpty()){
+            while(!in.isEmpty()){
+                out.push(in.pop());
+            }
+        }
+            return out.pop();
+    }
+
+    public int peek() {
+        if(out.isEmpty()){
+            while(!in.isEmpty()){
+                out.push(in.pop());
+            }
+        }
+            return out.peek();
+    }
+
+    public boolean empty() {
+        if(in.isEmpty() && out.isEmpty())
+         return true;
+         else
+         return false;
+    }
+}
+
+/**
+ * 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();
+ */