Design-2 Completed

Sample.java

@@ -1,7 +1,170 @@
 // Time Complexity :
 // Space Complexity :
-// Did this code successfully run on Leetcode :
+// Did this code successfully run on Leetcode :Yes
 // Any problem you faced while coding this :
 
 
 // Your code here along with comments explaining your approach
+//Problem 1:
+//Time Complexity: O(1) Space Complexity:O(n)
+/*I implemented this problem using two stacks so that to make it FIFO once I push it in one stack I will pop and push it in other stack
+so that I pop it in proper queue order.*/
+
+
+
+class MyQueue {
+    Stack<Integer> st1;
+    Stack<Integer> st2;
+    public MyQueue() {
+        this.st1= new Stack<>();
+        this.st2=new Stack<>();
+    }
+
+    public void push(int x) {
+        st1.push(x);
+    }
+
+    public int pop() {
+        if(st2.isEmpty()){
+            while(!st1.isEmpty())
+            {
+                st2.push(st1.pop());
+            }
+
+        }
+       return st2.pop();
+    }
+
+    public int peek() {
+        if(st2.isEmpty()){
+            while(!st1.isEmpty())
+            {
+                st2.push(st1.pop());
+            }
+
+        }
+        return st2.peek();
+    }
+
+    public boolean empty() {
+        if(st1.isEmpty() && st2.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();
+ */
+
+
+
+
+
+
+
+ /*Problem 2:
+  * Time Complexity:O(1) and Space:O(b+n) where b is number of buckets and n is additional nodes in the linked list
+   We use a primary stack of b elements and then find a primary hash through primary hash we form a linked list of nodes and perform operations
+   on it depending on if its null or not. We make a seperate function to find previous node so that we can easily implement the other functions
+   and handle addition or deletion of nodes.
+  */
+
+
+  class MyHashMap {
+    class Node{
+    Node next;
+    int key;
+    int value;
+    public Node(int key,int value)
+    {
+        this.key=key;
+        this.value=value;
+    }}
+    Node[] storage;
+    int buckets;
+    public MyHashMap() {
+     this.buckets=10000;
+     this.storage=new Node[buckets];
+    }
+
+    public void put(int key, int value) {
+        int primaryind=getPrimaryHash(key);
+        if(storage[primaryind]==null)
+        {
+            storage[primaryind]=new Node(-1,-1);
+        }
+        Node prev=getPrev(storage[primaryind],key);
+        if(prev.next==null){
+            Node curr=new Node(key,value);
+            prev.next=curr;
+            curr.next=null;
+        }
+        else{
+            prev.next.value=value;
+        }
+    }
+    private int getPrimaryHash(int key)
+    {
+        return key % buckets;
+    }
+    public int get(int key) {
+       int primaryind=getPrimaryHash(key);
+        if(storage[primaryind]==null)
+        {
+            storage[primaryind]=new Node(-1,-1);
+        }
+        Node prev=getPrev(storage[primaryind],key);
+        if(prev.next==null){
+            return -1;
+        }
+        else
+        return prev.next.value;
+    }
+
+    private Node getPrev(Node head,int key)
+    {
+        Node prev=null;
+        Node curr=head;
+
+        while(curr!=null && curr.key!=key)
+        {
+            prev=curr;
+            curr=curr.next;
+        }
+        return prev;
+    }
+
+    public void remove(int key) {
+        int primaryind=getPrimaryHash(key);
+        if(storage[primaryind]==null)
+        {
+            storage[primaryind]=new Node(-1,-1);
+        }
+        Node prev=getPrev( storage[primaryind],key);
+        if(prev.next==null){
+            return;
+        }
+        else{
+          Node curr=prev.next.next;
+          prev.next=null;
+          prev.next=curr;
+        }
+
+    }
+}
+
+/**
+ * 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);
+ */