diff --git a/ Contains Duplicate.js b/ Contains Duplicate.js
new file mode 100644
index 0000000..1121971
--- /dev/null
+++ b/ Contains Duplicate.js	
@@ -0,0 +1,15 @@
+const containsDuplicate = function (nums) {
+  const arr = {};
+
+  nums.forEach((x) => {
+    if (arr[x]) {
+      return (arr[x] += 1);
+    } else {
+      return (arr[x] = 1);
+    }
+  });
+
+  const newArr = Object.keys(arr).map((x) => arr[x]);
+
+  return newArr.some((x) => x >= 2);
+};
diff --git a/TwoSum.js b/TwoSum.js
new file mode 100644
index 0000000..27013e2
--- /dev/null
+++ b/TwoSum.js
@@ -0,0 +1,22 @@
+// Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
+// You may assume that each input would have exactly one solution, and you may not use the same element twice.
+// You can return the answer in any order.
+
+const twoSum = function (nums, target) {
+  const obj = {};
+
+  for (let i = 0; i < nums.length; i++) {
+    const num = target - nums[i];
+
+    if (obj.hasOwnProperty(num)) {
+      return [obj[num], i];
+    }
+
+    obj[nums[i]] = i;
+  }
+};
+
+const nums = [3, 2, 3];
+const target = 6;
+const a = twoSum(nums, target);
+console.log(a);