Alhind Tours And Travels Software Developer Interview Questions and Answers

Design a stack that supports push, pop, top, and retrieving minimum element in constant time.

• Use two stacks - one to store the actual elements and another to store the minimum values encountered so far

• When pushing an element, check if it is smaller than the current minimum and if so, push it to the minimum stack

• When popping an element, check if it is the current minimum and if so, pop from the minimum stack as well

• Top ...read more

Find the maximum circular subarray sum in an integer array.

• Calculate the non-circular maximum subarray sum using Kadane's algorithm.

• Calculate the circular maximum subarray sum by subtracting the minimum subarray sum from the total sum.

• Compare the non-circular and circular maximum subarray sums to get the overall maximum sum.

Find the smallest window in a string containing all characters of another string.

• Use a sliding window approach to find the smallest window

• Create a frequency map of characters in the second string

• Slide the window and update the frequency map until all characters are found

• Track the minimum window size and indices

To check if a linked list is a palindrome, compare the first half of the list with the reversed second half.

• Traverse the linked list to find the middle element using slow and fast pointers.

• Reverse the second half of the linked list.

• Compare the first half with the reversed second half to check for palindrome.

Deadlocks occur when two or more processes are waiting for each other to release resources, leading to a standstill.

• 4 conditions of Deadlocks: mutual exclusion, hold and wait, no preemption, circular wait

• Preventing Deadlocks: using a proper resource allocation strategy, implementing timeouts, avoiding circular wait, using deadlock detection and recovery algorithms

• Example: Two processes each holding a resource and waiti...read more

Use a hash set to store seen numbers and check if the complement of current number is in the set.

• Iterate through the array and for each number, check if the complement of the current number is in the hash set.

• If the complement is found, return true. Otherwise, add the current number to the hash set.

• Repeat this process for all numbers in the array.

• Example: Array [1, 2, 3, 4, 5] and Sum 9 should return true as 4 + 5 = 9.

DNS is a system that translates domain names to IP addresses, allowing users to access websites using human-readable names.

• DNS is like a phone book for the internet, translating domain names (e.g. google.com) to IP addresses (e.g. 172.217.3.206).

• DNS servers store records that map domain names to IP addresses, helping users navigate the internet.

• DNS also helps with email delivery by translating domain names in email add