CG-VAK Software & Exports Associate Group Lead Interview Questions and Answers

OOPs is a programming paradigm that uses objects to represent real-world entities and their interactions.

• OOPs stands for Object-Oriented Programming.

• It focuses on encapsulation, inheritance, and polymorphism.

• Encapsulation means hiding the implementation details of an object from the outside world.

• Inheritance allows creating new classes based on existing ones.

• Polymorphism allows using a single interface to represent dif...read more

To check if a directed graph is cyclic or not

• Use Depth First Search (DFS) algorithm to traverse the graph

• Maintain a visited set to keep track of visited nodes

• Maintain a recursion stack to keep track of nodes in the current DFS traversal

• If a node is visited and is already in the recursion stack, then the graph is cyclic

• If DFS traversal completes without finding a cycle, then the graph is acyclic

Return a random byte from a stream of bytes with equal probability.

• Create a variable to store the count of bytes read

• Create a variable to store the current random byte

• For each byte read, generate a random number between 0 and the count of bytes read

• If the random number is 0, store the current byte as the random byte

• Return the random byte

Check if a binary tree is a binary search tree or not.

• Traverse the tree in-order and check if the values are in ascending order.

• For each node, check if its value is greater than the maximum value of its left subtree and less than the minimum value of its right subtree.

• Use recursion to check if all nodes in the tree satisfy the above condition.

Algorithm to find Nth-to-Last element in a singly linked list of unknown length

• Traverse the list and maintain two pointers, one at the beginning and one at Nth node from beginning

• Move both pointers simultaneously until the second pointer reaches the end of the list

• The first pointer will be pointing to the Nth-to-Last element

• If N=0, return the last element

• Parse the list only once

Print all possible permutations of an array of integers

• Use recursion to swap elements and generate permutations

• Start with the first element and swap it with each subsequent element

• Repeat the process for the remaining elements

• Stop when all elements have been swapped with the first element

• Print each permutation as it is generated

Design a stack that prints the minimum element pushed in O(1)

• Use two stacks, one for storing elements and another for storing minimums

• When pushing an element, compare it with the top of minimum stack and push the smaller one

• When popping an element, pop from both stacks

• To get the minimum element, just return the top of minimum stack

To find the starting point of a loop in a linked list, use Floyd's cycle-finding algorithm.

• Use two pointers, one moving at twice the speed of the other.

• When they meet, move one pointer to the head of the list and keep the other at the meeting point.

• Move both pointers one step at a time until they meet again, which is the starting point of the loop.

To find a number in a matrix where all rows and columns are sorted non-decreasingly. Complexity of the solution.

• Use binary search to find the number in each row and column

• Start from the top-right corner or bottom-left corner to optimize search

• Time complexity: O(m log n) or O(n log m) depending on the starting corner

Insertion sort and quicksort are sorting algorithms used to sort arrays of data.

• Insertion sort: iterates through the array and inserts each element into its proper position.

• Quicksort: selects a pivot element and partitions the array into two sub-arrays, one with elements less than the pivot and one with elements greater than the pivot.

• Insertion sort is best for small arrays, while quicksort is best for large arrays.

• Bot...read more

Merge two sorted linked lists using recursion

• Create a recursive function that compares the first nodes of both lists

• Set the smaller node as the head of the merged list and call the function again with the next node of the smaller list

• Base case: if one list is empty, return the other list

• Return the merged list

Given an integer, determine which byte is zero.

• Convert the integer to a byte array using bitwise operations.

• Iterate through the byte array and check for a zero value.

• Return the index of the zero byte.

• Consider endianness when converting to byte array.

To check endianness, create a 4-byte integer with a known value and check the byte order.

• Create a 4-byte integer with a known value

• Check the value of the first byte to determine endianness

• If the first byte is the least significant, the machine is little endian

• If the first byte is the most significant, the machine is big endian

Static objects can be used to print something before main() execution.

• Static objects are initialized before main() execution

• They can be used to print something before main()

• Example: static int x = printf("Hello World!");

• Output: Hello World! will be printed before main() execution

Static variables are allocated memory in the data segment of the program's memory space.

• Static variables have a fixed memory location throughout the program's execution.

• They are initialized to zero by default.

• If initialized explicitly, they are stored in the data segment.

• Static variables can be accessed by any function in the program.

Finding space and time complexity of a recursive function.

• Space complexity is the amount of memory used by the function.

• Time complexity is the amount of time taken by the function to execute.

• Recursive functions have higher space complexity due to the call stack.

• Time complexity can be calculated using Big O notation.

• Examples of recursive functions include factorial and Fibonacci sequence.

Diamond hierarchy problem is a problem in object-oriented programming where a class inherits from multiple classes in a diamond-shaped hierarchy.

• Occurs when a class inherits from two classes that share a common base class

• Can lead to ambiguity in method calls and data members

• Solved using virtual inheritance or by using interfaces

To determine if a point is inside a polygon, use the ray casting algorithm.

• Create a line from the point to a point outside the polygon

• Count the number of times the line intersects with the polygon edges

• If the count is odd, the point is inside the polygon; otherwise, it is outside

The four storage classes in C are auto, register, static, and extern.

• Auto: default storage class for all local variables

• Register: used to define local variables that should be stored in a register instead of RAM

• Static: used to define local variables that retain their value between function calls

• Extern: used to declare a global variable that is defined in another file

i is stored in global data segment, j is stored in stack, k is stored in heap.

• i is a global variable and is stored in the global data segment

• j is a local variable and is stored in the stack

• k is a pointer variable and is stored in the stack, while the memory it points to is allocated on the heap using malloc()

Use a hash table to store the words and check for existence in constant time.

• Create a hash table with the words as keys and a boolean value as the value.

• For each new word, check if it exists in the hash table. If it does, it has appeared before. If not, add it to the hash table.

• Alternatively, use a set data structure to store only the unique words and check for existence in the set.

Return all root to leaf node paths in a binary tree with row, col and value.

• Traverse the binary tree recursively and keep track of the current path.

• When a leaf node is reached, add the path to the result array.

• Include row, col and value of each node in the path.

• Use an array of strings to store the paths.

To get max value from a stack in O(1), maintain a separate stack to keep track of maximum values.

• Create a separate stack to keep track of maximum values

• Push the maximum value onto the stack whenever a new maximum is encountered

• Pop the maximum value stack whenever the top element of the main stack is popped

• Return the top element of the maximum value stack to get the maximum value in O(1)

To get max element from a queue in O(1) time complexity

• Maintain a separate variable to keep track of the maximum element in the queue

• Update the maximum element variable whenever a new element is added or removed from the queue

• Return the maximum element variable when getMax() function is called

Find the Next Greatest Element to the right for each element in an array of strings.

• Iterate through the array from right to left

• Use a stack to keep track of elements

• Pop elements from stack until a greater element is found

• If no greater element is found, assign -1

• Return the result array

To remove unnecessary parenthesis from an expression, we need to apply a set of rules to identify and eliminate them.

• Identify and remove parenthesis around single variables or constants

• Identify and remove parenthesis around expressions with only one operator

• Identify and remove parenthesis around expressions with operators of equal precedence

• Identify and remove parenthesis around expressions with operators of different ...read more

Find the maximum product of three integers in an array.

• Sort the array in descending order.

• Check the product of the first three numbers and the product of the first and last two numbers.

• Return the maximum of the two products.

Find length of longest consecutive sub array forming an AP from given array of integers.

• Sort the array in ascending order

• Iterate through the array and find the longest consecutive sub array forming an AP

• Use a variable to keep track of the length of the current consecutive sub array forming an AP

• Use another variable to keep track of the length of the longest consecutive sub array forming an AP seen so far