|7|[Reverse Integer](https://leetcode.com/problems/reverse-integer/)|[Solution](../../blob/master/EASY/src/easy/ReverseInteger.java) | O(1) | O(1) | Easy |

|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/)|[Solution](../../blob/master/MEDIUM/src/medium/AddTwoNumbers.java) | O(n) | O(1) | Medium | LinkedList

|1|[Two Sum](https://leetcode.com/problems/two-sum/)|[Solution](../../blob/master/EASY/src/easy/TwoSum.java)| O(n)/O(n^2)|O(1)/O(n) | Easy| HashMap