|259|[3Sum Smaller](https://leetcode.com/problems/3sum-smaller/)|[Solution](../../blob/master/MEDIUM/src/medium/_3Sum_Smaller.java)| O(n^2)|O(1) | Medium|

|257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/)|[Solution](../../blob/master/EASY/src/easy/BinaryTreePaths.java) | O(n*h) | O(h) | DFS/Recursion

|252|[Meeting Rooms](https://leetcode.com/problems/meeting-rooms/)|[Solution](../../blob/master/EASY/src/easy/MeetingRooms.java) | O(nlogn) | O(1) |

|223|[Rectangle Area](https://leetcode.com/problems/rectangle-area/)|[Solution](../../blob/master/EASY/src/easy/RectangleArea.java)| O(1)|O(1) | Easy|

|219|[Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/)|[Solution](../../blob/master/EASY/src/easy/ContainsDuplicateII.java)| O(n)|O(n) | Easy| HashMap

|209|[Minimum Size Subarray Sum](https://leetcode.com/problems/minimum-size-subarray-sum/)|[Solution](../../blob/master/MEDIUM/src/medium/MinimumSizeSubarraySum.java)| O(n)|O(1) | Medium|