done Design1

DesignHashSet.java

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+
+// Time Complexity :o(1)
+// Space Complexity :o(n) 
+// Did this code successfully run on Leetcode : it runs good in leat code
+// Any problem you faced while coding this : no
+
+
+// Your code here along with comments explaining your approach
+class MyHashSet {
+    private boolean[][] storage;
+    private int buckets;
+    private int bucketItems;
+
+    private int bucket(int key) {
+        return key % buckets;
+    }
+
+    private int bucketitems(int key) {
+        return key / bucketItems;
+    }
+
+    public MyHashSet() {
+        this.buckets = 1000;
+        this.bucketItems = 1000;
+        this.storage = new boolean[buckets][];
+    }
+
+    public void add(int key) {
+        int bucket = bucket(key);
+        if (storage[bucket] == null) {
+            if (bucket == 0) {
+                storage[bucket] = new boolean[bucketItems + 1];
+            } else {
+                storage[bucket] = new boolean[bucketItems];
+            }
+        }
+        int bucketItem = bucketitems(key);
+        storage[bucket][bucketItem] = true;
+    }
+
+    public void remove(int key) {
+        int bucket = bucket(key);
+        if (storage[bucket] == null) return;
+        int bucketItem = bucketitems(key);
+        storage[bucket][bucketItem] = false;
+    }
+
+    public boolean contains(int key) {
+        int bucket = bucket(key);
+        if (storage[bucket] == null) return false;
+        int bucketItem = bucketitems(key);
+        return storage[bucket][bucketItem];
+    }
+}
+
+/**
+ * Your MyHashSet object will be instantiated and called as such:
+ * MyHashSet obj = new MyHashSet();
+ * obj.add(key);
+ * obj.remove(key);
+ * boolean param_3 = obj.contains(key);
+ */

MinStack.java

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+//Time Complexity :o(1)
+// Space Complexity :o(n) 
+// Did this code successfully run on Leetcode : it runs good in leat code
+// Any problem you faced while coding this : no
+
+
+// Your code here along with comments explaining your approach
+class MinStack {
+    Stack <Integer>st;
+    Stack <Integer>minst;
+    int min;
+    public MinStack() {
+        this.min=Integer.MAX_VALUE;
+        this.st = new Stack<>();
+        this.minst=new Stack<>();
+        this.minst.push(this.min);
+    }
+
+    public void push(int val) {
+        min =Math.min(min,val);
+        st.push(val);
+        minst.push(min);
+    }
+
+    public void pop() {
+        st.pop();
+        minst.pop();
+        min = minst.peek();
+    }
+
+    public int top() {
+        return st.peek();
+    }
+
+    public int getMin() {
+        return min;
+    }
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * MinStack obj = new MinStack();
+ * obj.push(val);
+ * obj.pop();
+ * int param_3 = obj.top();
+ * int param_4 = obj.getMin();
+ */