Android-Cheat-sheet

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

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!