add draft question 217 and 219

Author: rishabh1403

201-300/217-contains-duplicate.js

@@ -0,0 +1,13 @@
+/*
+Author :- Rishabh Jain <contact@rishabh1403.com>
+Solution for :- https://leetcode.com/problems/contains-duplicate/
+blog for this code :- https://rishabh1403.com/posts/coding/leetcode/2020/03/leetcode-valid-anagram
+youtube video :- https://youtu.be/7z25qqUCOUE
+*/
+
+
+var containsDuplicate = function (nums) {
+  const set = new Set(nums);
+
+  return set.size !== nums.length
+};

201-300/219-contains-duplicate-ii.js

@@ -0,0 +1,26 @@
+/*
+Author :- Rishabh Jain <contact@rishabh1403.com>
+Solution for :- https://leetcode.com/problems/contains-duplicate-ii/
+blog for this code :- https://rishabh1403.com/posts/coding/leetcode/2020/03/leetcode-valid-anagram
+youtube video :- https://youtu.be/7z25qqUCOUE
+*/
+
+
+var containsNearbyDuplicate = function (nums, k) {
+  const map = new Map();
+
+  for (let i = 0; i < nums.length; i++) {
+    if (map.has(nums[i])) {
+      const j = map.get(nums[i]);
+      if (Math.abs(i - j) <= k) {
+        return true;
+      } else {
+        map.set(nums[i], i);
+      }
+    } else {
+      map.set(nums[i], i);
+    }
+  }
+
+  return false;
+};

README.md

@@ -26,6 +26,10 @@ Solutions of all the questions from Leetcode in JavaScript.
 
 - 167.Two Sum-II - [Question](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/) | [Source Code](https://github.com/rishabh1403/leetcode-javascript-solutions/blob/master/101-200/167-two-sum-ii.js) | [Blog](https://rishabh1403.com/leetcode-solution-of-two-sum-ii-in-javascript) | [Youtube Video](https://www.youtube.com/watch?v=MjxN8HIzIRc)
 
+- 217.Contains Duplicate - [Question](https://leetcode.com/problems/contains-duplicate/) | [Source Code]() | [Blog]() | [Youtube Video]()
+
+- 219.Contains Duplicate II - [Question](https://leetcode.com/problems/contains-duplicate-ii/) | [Source Code]() | [Blog]() | [Youtube Video]()
+
 - 242.Valid Anagram - [Question](https://leetcode.com/problems/valid-anagram/) | [Source Code](https://github.com/rishabh1403/leetcode-javascript-solutions/blob/master/201-300/242-valid-anagram.js) | [Blog](https://rishabh1403.com/posts/coding/leetcode/2020/03/leetcode-valid-anagram) | [Youtube Video](https://youtu.be/7z25qqUCOUE)
 
 - 268.Missing Number - [Question](https://leetcode.com/problems/missing-number/) | [Source Code](https://github.com/rishabh1403/leetcode-javascript-solutions/blob/master/201-300/268-missing-number.js) | [Blog](https://rishabh1403.com/posts/coding/leetcode/2020/03/leetcode-missing-number) | [Youtube Video](https://youtu.be/I6AUMvi13fc)