diff --git a/155MinStack.js b/155MinStack.js
new file mode 100644
index 00000000..1b30801a
--- /dev/null
+++ b/155MinStack.js
@@ -0,0 +1,53 @@
+// Time Complexity : O(1)
+// Space Complexity : O(n)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+var MinStack = function () {
+  this.mainStack = [];
+  this.minStack = [];
+};
+
+/**
+ * @param {number} val
+ * @return {void}
+ */
+MinStack.prototype.push = function (val) {
+  this.mainStack.push(val);
+  const minVal =
+    this.minStack.length === 0
+      ? val
+      : Math.min(val, this.minStack[this.minStack.length - 1]);
+  this.minStack.push(minVal);
+};
+
+/**
+ * @return {void}
+ */
+MinStack.prototype.pop = function () {
+  this.mainStack.pop();
+  this.minStack.pop();
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.top = function () {
+  return this.mainStack[this.mainStack.length - 1];
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.getMin = function () {
+  return this.minStack[this.minStack.length - 1];
+};
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * var obj = new MinStack()
+ * obj.push(val)
+ * obj.pop()
+ * var param_3 = obj.top()
+ * var param_4 = obj.getMin()
+ */
diff --git a/705DesignHashSet.js b/705DesignHashSet.js
new file mode 100644
index 00000000..f4124c19
--- /dev/null
+++ b/705DesignHashSet.js
@@ -0,0 +1,62 @@
+// Time Complexity : O(1)
+// Space Complexity : O(n)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+var MyHashSet = function () {
+  this.size = 1009;
+  this.buckets = new Array(this.size);
+  for (let i = 0; i < this.size; i++) {
+    this.buckets[i] = [];
+  }
+};
+
+/**
+ * @param {number} key
+ * @return {void}
+ */
+
+MyHashSet.prototype.hash1 = function (key) {
+  return key % this.size;
+};
+MyHashSet.prototype.hash2 = function (key) {
+  return Math.floor(key / this.size);
+};
+MyHashSet.prototype.add = function (key) {
+  const h1 = this.hash1(key);
+  const h2 = this.hash2(key);
+  // if(!this.buckets[h1])
+  //this.buckets[h1] = new Array(993).fill(false)
+  this.buckets[h1][h2] = true;
+};
+
+/**
+ * @param {number} key
+ * @return {void}
+ */
+MyHashSet.prototype.remove = function (key) {
+  const h1 = this.hash1(key);
+  const h2 = this.hash2(key);
+  if (this.buckets[h1]) this.buckets[h1][h2] = false;
+};
+
+/**
+ * @param {number} key
+ * @return {boolean}
+ */
+MyHashSet.prototype.contains = function (key) {
+  const h1 = this.hash1(key);
+  const h2 = this.hash2(key);
+  if (this.buckets[h1])
+    if (this.buckets[h1][h2]) return true;
+    else return false;
+  else return false;
+};
+
+/**
+ * Your MyHashSet object will be instantiated and called as such:
+ * var obj = new MyHashSet()
+ * obj.add(key)
+ * obj.remove(key)
+ * var param_3 = obj.contains(key)
+ */