|189|[Rotate Array](https://leetcode.com/problems/rotate-array/)|[Solution](../../blob/master/EASY/src/easy/RotateArray.java)| O(n)|O(n), could be optimized to O(1) | Easy

|173|[Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/)|[Queue](../../blob/master/MEDIUM/src/medium/BSTIterator_using_q.java) [Stack](../../blob/master/MEDIUM/src/medium/BSTIterator_using_stack.java)| O(1) |O(h) | Medium|

|172|[Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes/)|[Solution](../../blob/master/EASY/src/easy/FactorialTrailingZeroes.java)| O(logn)|O(1)| Easy

|165|[Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/)|[Solution](../../blob/master/EASY/src/easy/CompareVersionNumbers.java)| O(n)|O(1) | Easy|

|162|[Find Peak Element](https://leetcode.com/problems/find-peak-element/)|[Solution](../../blob/master/MEDIUM/src/medium/FindPeakElement.java) | O(1) |O(logn)/O(n) | Binary Search|

|155|[Min Stack](https://leetcode.com/problems/min-stack/)|[Solution](../../blob/master/EASY/src/easy/MinStack.java)| O(1)|O(n) | Easy| Stack