8000+ Software Developer Interview Questions and Answers

Reverse a stack using recursion without using any extra space other than the internal stack space.

• Use recursion to pop all elements from the original stack and store them in function call stack

• Once the stack is empty, push the elements back in reverse order using recursion

• Make use of auxiliary functions to handle the recursion process

Sort an array of 0s and 1s in linear time without using additional arrays.

• Iterate through the array and maintain two pointers, one for 0s and one for 1s.

• Swap elements at the two pointers based on the current element being 0 or 1.

• Continue this process until the entire array is sorted in place.

Calculate the integer square root of a given number.

• Use binary search to find the square root of the number.

• Start with a range from 0 to N, and iteratively narrow down the range until you find the integer square root.

• Return the integer part of the square root as the output.

The task is to find a string of minimal length that includes every possible string of N digits with digits ranging from 0 to K as substrings.

• Generate all possible strings of N digits with digits from 0 to K

• Concatenate these strings in a way that all are substrings of the final string

• Return 1 if the final string contains all possible strings, else return 0

Implement a GUI to display a file structure using a linked list of nodes representing files and directories.

• Each node has properties: ID, parent ID, name, and number of children.

• The linked list maintains the order: parent directories appear before their children.

• To display children, traverse the linked list and check for matching parent IDs.

• Example: For a parent node with ID 1, find all nodes with parent ID 1 to display its children.

• Use a recursive function to handle expandin...read more

Remove alternate nodes from a singly linked list of integers.

• Traverse the linked list and skip every alternate node while updating the next pointers.

• Make sure to handle cases where there are less than 3 nodes in the list.

• Update the next pointers accordingly to remove alternate nodes.

• Example: Input: 10 20 30 40 50 60 -1, Output: 10 30 50

Yes, the sentence is a pangram if it includes every letter of the English alphabet at least once.

• Check if the sentence contains all 26 letters of the English alphabet.

• Convert the sentence to lowercase to simplify the checking process.

• Use a set to keep track of the letters present in the sentence.

• Iterate through the sentence and add each unique letter to the set.

• After iterating, check if the set contains all 26 letters.

The Weighted Job Scheduling problem involves maximizing profit by scheduling non-overlapping jobs with start time, end time, and profit given.

• Sort the jobs based on their end times in ascending order.

• Initialize an array 'dp' to store the maximum profit that can be earned by scheduling jobs up to that index.

• For each job, find the maximum profit by either including or excluding the current job based on non-overlapping condition.

• Return the maximum profit from the 'dp' array.

• Exam...read more

The problem involves determining if a cab with a certain capacity can successfully pick up and drop off passengers at specified points for multiple trips.

• Create a function that takes in the car's capacity, number of trips, and trip details as input

• Iterate through each trip and check if the total number of passengers picked up and dropped off is within the car's capacity

• Return 'True' if all trips can be successfully completed, 'False' otherwise

The task is to determine the number of possible ways to roll all the dice such that the sum of the face-up numbers equals the given 'target' sum.

• Use dynamic programming to solve the problem efficiently.

• Create a 2D array to store the number of ways to achieve each sum with the given number of dice.

• Iterate through the dice and faces to calculate the number of ways to reach each sum.

• Return the result modulo 10^9 + 7.

• Optimize the solution to use no more than O(S) extra space by u...read more

Find the fourth largest element in an array, return -2147483648 if not enough distinct elements.

• Sort the array in descending order

• Return the fourth element if it exists, else return -2147483648

Find the sum of numbers divisible by 2 or 3 from a given list of numbers.

• Iterate through the list of numbers and check if each number is divisible by 2 or 3.

• If a number is divisible by 2 or 3, add it to the sum.

• Return the final sum as the output.

The given string needs to be reversed word wise, keeping the individual words intact.

• Split the string into an array of words using a space as the delimiter.

• Reverse the array of words.

• Join the reversed array of words using a space as the separator to form the final reversed string.

Sort an array of 0s, 1s, and 2s in linear time complexity.

• Use three pointers to keep track of the positions of 0s, 1s, and 2s in the array.

• Iterate through the array and swap elements based on the values encountered.

• Maintain left pointer for 0s, right pointer for 2s, and current pointer for traversal.

• Example: If current element is 0, swap it with element at left pointer and increment both pointers.

Calculate the time in minutes required to completely burn a binary tree starting from a given node.

• Traverse the tree to find the start node and calculate the time for fire to spread to all nodes.

• Use a queue to keep track of nodes to be burnt next.

• Increment time for each level of nodes burnt until the entire tree is burnt.

Count pairs in an array with a specific absolute difference.

• Iterate through the array and for each element, check if the element + K or element - K exists in the array.

• Use a hash set to store elements for constant time lookups.

• Keep track of the count of valid pairs found.

The task is to determine the number of levels cleared by Kevin based on the total number of hurdles he has jumped.

• Each level 'i' has 'i' hurdles, so Kevin can only reach level 'i' if he has cleared level 'i-1'.

• Count the number of levels cleared by dividing the total number of hurdles by the sum of the first 'n' natural numbers.

• The formula to calculate the sum of the first 'n' natural numbers is (n * (n + 1)) / 2.

Minimize maximum error by splitting photos into batches of size at least 'K'.

• Sort the array of resolutions in ascending order.

• Iterate through the array and calculate the error for each possible batch.

• Return the minimum possible maximum error found.

Count the number of pairs in an array that satisfy a given equation.

• Iterate through all pairs of indices in the array and check if the equation is satisfied.

• Use a hashmap to store the frequency of values that can be used to form pairs.

• Optimize the solution by using two pointers approach to find pairs efficiently.

Count the number of distinct ways to climb a staircase with a certain number of steps using either one or two steps at a time.

• Use dynamic programming to solve this problem efficiently.

• Keep track of the number of ways to reach each step by considering the number of ways to reach the previous two steps.

• Return the result modulo 10^9+7 to handle large outputs.

• Example: For N=4, the distinct ways to climb are {(0,1,2,3,4)}, {(0,1,2,4)}, {(0,2,3,4)}, {(0,1,3,4)}, and {(0,2,4)} total...read more

Create a function to determine the day of the week for any given date.

• Parse the input integers to create a date object

• Use a library or algorithm to calculate the day of the week for the given date

• Return the corresponding day of the week as a string

Implement a function to delete a node from a linked list at a specified position.

• Traverse the linked list to find the node at the specified position.

• Update the pointers of the previous and next nodes to skip the node to be deleted.

• Handle edge cases such as deleting the head or tail of the linked list.

• Ensure to free the memory of the deleted node to avoid memory leaks.

Find total distinct card types and common card types between two packs of cards.

• Create a set to store distinct card types when combining both packs.

• Iterate through each pack and add card types to the set.

• Find the intersection of card types between the two packs to get common card types.

Find the maximum sum of non-adjacent elements in an array.

• Use dynamic programming to keep track of the maximum sum at each index, considering whether to include the current element or skip it.

• At each index, the maximum sum is either the sum of the current element and the element two positions back, or the sum at the previous index.

• Iterate through the array and update the maximum sum at each index accordingly.

• Return the maximum sum obtained at the last index as the final resul...read more

Calculate and return the median of all subarrays of a specified size in an integer array.

• Iterate through the array and for each subarray of size M, calculate the median.

• If the size of the subarray is even, take the average of the two middle numbers as the median.

• Return the list of medians for all subarrays of size M.

Determine if an array can be transformed into a non-decreasing array by modifying at most one element.

• Iterate through the array and check if there are more than one decreasing elements.

• If there is only one decreasing element, check if modifying it can make the array non-decreasing.

• Return true if the array can be made non-decreasing by modifying at most one element, otherwise false.

Reverse words in a string while handling leading, trailing, and multiple spaces.

• Split the input string by spaces to get individual words

• Reverse the order of the words

• Join the reversed words with a single space in between