# Amazon’s most frequently asked interview questions | Set 2

Amazon’s Most Frequently Asked Questions | Set 1

**Level – Easy**

- Get minimum element from the stack – Practice here
- Serialize and deserialize a binary tree – Practice here
- Print a binary tree in a vertical order – Practice here
- Celebrity problem – Practice here
- Level order traversal
- Swap the kth element from starting and from the end position – Practice here
- Binary tree to bst – Practice here
- Max sum in the configuration – Practice here
- Find the nth element of spiral matrix – Practice here
- Count the number of occurrences in a sorted array
- Find the smallest window in a string containing all characters of another string
- Find the maximum of all subarrays of size k
- Find the kth smallest element in row-wise and column-wise sorted matrix
- Minimum swaps required to arrange pairs
- There is an array of N numbers ranging from 1 to N. Only 1 number is missing, return the index of that number
- Find the second largest and second smallest in a given array in a single traversal.
- Find power(x,y) without using pow function.(divide and conquer approach required)
- Count possible decoding sequence

**Level – Medium**

- Given two string print them inter leaving strings characters
- Minimum cost required to travel from top left to the bottom right in a matrix
- Maximum difference between node and its ancestors – Practice here
- Min distance between two given nodes of a binary tree – Practice here
- Find the number of island – Practice here
- Topological Sort – Practice here
- Detect cycle in a directed graph – Practice here
- Flattening a link list – Practice here
- Detect a loop in a linked list – Practice here
- Check if a binary tree is BST or not
- Min Cost path
- Count ways to reach nth stair
- Maximum Subarray Problem
- Palindrome Partitioning
- Given a binary tree find the minimum root to leaf height.
- Implement LRU cache

**Level – Hard**

- Boolean parenthesis – Practice here
- Maximum Index – Practice here
- Largest Number formed in the array – Practice here
- Find the length of maximum numbers of consecutive numbers jumped up in an array
- Delete the elements in a linklist whose sum is equal to zero
- Given a list of numbers of odd length design an algorithm to remove a number and divide the rest numbers equally so as it makes their sum same
- Find diameter of a binary tree

Also see

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