Android-Cheat-sheet

Cheat Sheet for Android Interviews. Updated the list to include the latest android components available in 2024.

Maintained by Anitaa Murthy, a mobile engineer with 10+ years building products end to end across Android, iOS and backend. Currently available for freelance projects: portfolio · [email protected]

Topics

• Common Coding Programs
• Data Structure Coding Programs
• Android Interview Series – Part 1 (Android basics)
• Android Interview Series – Part 2 (Android expert)
• Android Interview Series – Part 3 (Java basics)
• Android Interview Series – Part 4 (Kotlin basics)
• Android Interview Series – Part 5 (Kotlin coroutines)
• Android Interview Series – Part 6 (Kotlin Flows)
• Android Interview Series – Part 7 (Jetpack Compose)
  

Common Coding Programs

• Arrays
  

  • Find Maximum Sell Profit
  • Find Low & High Index of a key from a given array
  • Merge Overlapping Intervals
  • Move all zeros in an array to the Left or Right
  • Rotate an array
  • Find the smallest common number in a given array
  • Find the sum of two elements in a given array
  • Find the minimum distance between two numbers in an array
  • Find the maximum difference between the values in an array such that the largest values always comes after the smallest value
  • Find second largest element in an array
  • Find the 3 numbers in an array that produce the max product
  • Find missing number from an array
    

• Dynamic Programming
  

  • Fibonacci Series
  • Given an array, find the contiguous subarray with the largest sum
  • Find the maximum sum of a subsequence such that no consecutive elements are part of the subsequence
  • Given a score "n", find the total number of ways score "n" can be reached
  • Compute Levenshtein distance between two strings
  • Given coin denominations and the total amount, find out the number​ of ways to make the change
    

• Queues
  

  • Find the Maximum in a Sliding Window
  • Implement a queue using stack
    

• LinkedList
  

  • Reverse a Linked List
  • Remove duplicates from a Linked List
  • Delete Node of a given key from a Linked List
  • Find the Middle Node of a Linked List
  • Find the Nth Node of a Linked List
  • Check if a Linked List is cyclic
  • Insertion Sort of a Linked List
  • Intersection Point of Two Lists
  • Nth from last node
  • Swap Nth Node with Head
  • Merge Two Sorted Linked Lists
  • Sorting LinkedList using merge sort
  • Reverse nodes at even indices
  • Rotate linked list by n
  • Reverse every 'k' elements in a linked list
  • Add the head pointers of two linked lists
    

• Stacks
  

  • Evaluate an expression
  • Implement a stack using queues
  • Check if paranthesis are equal
  • Tower of Hanoi
  • ReverseAStack
    

• Back Tracking
  

  • Solve Boggle
  • Print paranthesis combination for a given value
  • Solve N queen problem
  • find all the subsets of the given array that sum up to the number K
    

• Graphs
  

  • Clone a Directed Graph
  • Minimum Spanning Tree
  • Form circular chain by given list of words
    

• Trees
  

  • Implements an InOrder Iterator on a Binary Tree
  • Convert a binary tree to a doubly linked list
  • Connect a sibling pointer of a binary tree to next node in the same level
  • Given a binary tree, connect its siblings at each level
  • Delete any subtrees whose nodes sum up to zero
  • Given roots of two binary trees, determine if these trees are identical
  • Find the Inorder successor of a node in binary Search Tree
  • Algorithm to traverse the tree inorder
  • Check if a given tree is a binary search tree
  • Display node values at each level in a binary tree
  • Swap the 'left' and 'right' children for each node in a binary tree
  • Find nth highest node in a Binary Search Tree
  • Print nodes forming the boundary of a Binary Search Tree
  • Serialize binary tree to a file and then deserialize back to tree
    

• Strings
  

  • Reverse String
  • Palindrone String
  • Regular Expression
  • Remove Duplicates
  • Remove White Spaces
  • Remove a String
  • String Segmentation
  • Find next highest permutation of a given string
  • Check if two strings are anagrams
    

• Integers
  

  • Reverse Integer
  • Find sum of digits of an integer
  • Find Next highest Number from a Integer
  • Check if it is an Armstrong number
  • Find the factorial of a number
  • Print all prime numbers upto the given number
  • Find all the prime factors of a given integer
  • Check if a given number is binary
  • Find kth permutation
  • Integer Division
  • Find Pythagorean Triplets
  • Print all possible sum combinations using positive integers
  • Find Missing Number
  • Find all subsets of a given set of integers
  • Given an input string, determine if it makes a valid number
  • Calculate 'x' raised to the power 'n'
  • Calculate square root of a number
  • Minimum Number of Platforms Required for a Railway/Bus Station
    

• Miscellaneous
  

  • Find three integers in the array with sum equal to the given value
  • Find position of a given key in 2D matrix
  • Determine the host byte order of any system
  • Find the point that requires the least total distance covered by all the ​people to meet at that point
  • Given a two dimensional array, if any element in it is zero make its whole row and column zero
    

Data Structure Coding Programs

• Sorting
  

  • BubbleSort
  • InsertionSort
  • SelectionSort
  • QuickSort
  • MergeSort
    • Question: Why is quicksort preferred over merge sort for sorting arrays?
      
      • Quicksort does not require any extra storage whereas merge sort requires O(n) space allocation. Allocating/de-allocating memory space can increase the run time.
        
    • Question: Why is merge sort preferred over quicksort for sorting linked lists?
      
      • There is a difference in linked lists due to memory allocation. In linked lists we can insert items in the middle in O(n) space and time. There is no extra memory allocation required.
  
  

• Searching
  

  • Binary Search
  • Rotated Binary Search
  • Ternary Search
    • Question: Why is binary search preferred over ternary search?
      
      • When dividing an array by k ( 2(binary) or 3(ternary)), it reduces the array size to 1/k. But it increases the no of comparisons by k.
  
  

• Runtime Complexity Table:
  
  

I will be adding more questions soon! If you would like to contribute to the Android Cheat Sheet, just make a pull request!