From cbd264e494794f60b207908389ceb244fb37c334 Mon Sep 17 00:00:00 2001
From: Balaviknesh Sekar <bala21karthick@gmail.com>
Date: Tue, 3 Feb 2026 17:39:08 -0600
Subject: [PATCH] Added solutions

---
 HashSet.kt  | 40 ++++++++++++++++++++++++++++++++++++++++
 MinStack.kt | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 HashSet.kt
 create mode 100644 MinStack.kt

diff --git a/HashSet.kt b/HashSet.kt
new file mode 100644
index 00000000..51edf37f
--- /dev/null
+++ b/HashSet.kt
@@ -0,0 +1,40 @@
+//Time complexity: O(1) for add, remove, and contains operations
+//Space complexity: O(1) for add, remove, and contains operations for hashSet o(n) where n is the size of the hashSet
+
+class MyHashSet() {
+
+    private val hashSet = Array(1000000) { mutableListOf<Int>() }
+    private var size = 0
+
+    private fun hashIndex(key: Int): Int {
+        return key % 1000000
+    }
+
+    fun add(key: Int) {
+        if(!contains(key)) {
+            size += 1
+            hashSet[hashIndex(key)].add(key)
+        }
+    }
+
+    fun remove(key: Int) {
+        if(contains(key)) {
+            size -= 1
+            hashSet[hashIndex(key)].remove(key)
+        }
+    }
+
+    fun contains(key: Int): Boolean {
+        return hashSet[hashIndex(key)].contains(key)
+    }
+}
+
+
+
+/**
+ * Your MyHashSet object will be instantiated and called as such:
+ * var obj = MyHashSet()
+ * obj.add(key)
+ * obj.remove(key)
+ * var param_3 = obj.contains(key)
+ */
\ No newline at end of file
diff --git a/MinStack.kt b/MinStack.kt
new file mode 100644
index 00000000..bde07098
--- /dev/null
+++ b/MinStack.kt
@@ -0,0 +1,40 @@
+//Time Complexity: O(1) for all operations
+//Space Complexity: O(n) where n is the number of elements in the stack
+
+
+class MinStack() {
+
+    val stack = mutableListOf<Pair<Int, Int>>()
+    var size = 0
+
+    fun push(`val`: Int) {
+        val currentMin = if (size == 0) `val` else minOf(stack[size - 1].second, `val`)
+        stack.add(Pair(`val`, currentMin))
+        size += 1
+    }
+
+    fun pop() {
+        if (size != 0) {
+            stack.removeAt(size - 1)
+            size -= 1
+        }
+    }
+
+    fun top(): Int {
+        return stack[size - 1].first
+    }
+
+    fun getMin(): Int {
+        return stack[size - 1].second
+    }
+
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * var obj = MinStack()
+ * obj.push(`val`)
+ * obj.pop()
+ * var param_3 = obj.top()
+ * var param_4 = obj.getMin()
+ */
\ No newline at end of file