7000+ Software Engineer Interview Questions and Answers

Implement a function to multiply two sparse matrices and return the resulting matrix.

• Create a function that takes two sparse matrices as input and returns the resulting matrix after multiplication.

• Iterate through the non-zero elements of the matrices to perform the multiplication efficiently.

• Ensure to handle the sparse nature of the matrices to optimize the multiplication process.

• Consider the constraints provided to ensure the function works within the specified limits.

• Test t...read more

Find the maximum sum path in a matrix from top row to bottom row by moving down or diagonally.

• Use dynamic programming to keep track of maximum sum at each cell.

• At each cell, consider the maximum sum from the cell above, left diagonal, and right diagonal.

• Add the current cell value to the maximum of the three possibilities.

• Repeat this process for all cells in the matrix to find the maximum sum path.

The task is to reverse a given string containing lowercase letters, uppercase letters, digits, and special characters.

• Iterate through the string from the last character to the first character and append each character to a new string.

• Alternatively, you can use built-in string reversal functions or methods available in your programming language.

• To solve the follow-up question with O(1) space complexity, you can use a two-pointer approach. Initialize two pointers, one at the be...read more

A compiler translates the entire program into machine code before execution, while an interpreter translates and executes the program line by line.

• A compiler converts the source code into an executable file, while an interpreter executes the code directly.

• Compilers typically produce faster and more efficient code, while interpreters provide faster development and debugging.

• Examples of compilers include GCC, Clang, and Visual C++, while examples of interpreters include Python,...read more

Detect if a singly linked list forms a cycle by checking if a node's next points back to a previous node.

• Traverse the linked list using two pointers, one moving one step at a time and the other moving two steps at a time.

• If the two pointers meet at any point, it indicates the presence of a cycle in the linked list.

• If one of the pointers reaches the end of the list (null), it means there is no cycle.

The task is to compute the total number of ways to paint 'N' fences using 2 colors, such that no more than 2 adjacent fences have the same color.

• Use dynamic programming to solve the problem efficiently.

• Consider two cases: when the last two fences have the same color and when they have different colors.

• Implement a solution that calculates the number of ways to paint 'N' fences modulo 10^9 + 7.

• For N = 2, there are 4 valid ways to paint the fences: [0, 1], [1, 0], [1, 1], and [0...read more

Calculate the total amount of rainwater that can be trapped between given elevations in an array.

• Iterate through the array and calculate the maximum height on the left and right of each bar.

• Calculate the amount of water that can be trapped at each bar by taking the minimum of the maximum heights on the left and right.

• Sum up the trapped water at each bar to get the total trapped water for the entire array.

Find all paths in a binary tree where the sum of node values equals a given number 'K'.

• Traverse the binary tree in a depth-first manner while keeping track of the current path and sum of node values.

• When reaching a leaf node, check if the current path sum equals 'K'. If so, add the path to the result.

• Continue traversal to explore all possible paths in the tree.

• Return the list of paths that satisfy the condition.

• Example: For input tree 1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1 and...read more

The task is to convert a given string into its equivalent representation based on a mobile numeric keypad sequence.

• Iterate through each character in the input string and find its corresponding numeric representation on the keypad

• Use a mapping of characters to numbers based on the keypad layout provided in the reference

• Output the sequence of numbers that corresponds to typing the input string on the keypad

Find the length of longest substring composed of same digit within a string of digits.

• Iterate through the string and keep track of the current digit and its count

• Update the maximum count whenever a new digit is encountered

• Return the maximum count

C++ is a high-level programming language used for developing system software, application software, device drivers, and video games.

• C++ is an extension of the C programming language.

• It supports object-oriented programming concepts like classes, inheritance, and polymorphism.

• C++ is used in developing operating systems, browsers, databases, and more.

• Examples of popular software written in C++ include Adobe Photoshop, Microsoft Office, and MySQL.

• C++ is known for its performance ...read more

Determine if it is possible to accommodate all passenger trips within a car's capacity without exceeding it at any point.

• Iterate through each trip and keep track of the total number of passengers in the car at each point.

• Check if the total number of passengers exceeds the car capacity at any point.

• Return 'True' if all trips can be accommodated within the car capacity, otherwise return 'False'.

Check if two binary trees are mirrors of each other based on specific criteria.

• Compare the roots of both trees.

• Check if the left subtree of the first tree is the mirror of the right subtree of the second tree.

• Verify if the right subtree of the first tree is the mirror of the left subtree of the second tree.

Perform left rotations on an array based on given queries.

• Create a function that takes the array, number of elements, number of queries, and the queries as input.

• For each query, rotate the array by the specified number of elements to the left.

• Return the final array after each rotation query.

Scheduling is the process of allocating resources to tasks based on priority and availability.

• Different types of scheduling include: preemptive and non-preemptive scheduling, round-robin scheduling, priority scheduling, and deadline scheduling.

• Preemptive scheduling allows higher priority tasks to interrupt lower priority tasks, while non-preemptive scheduling does not.

• Round-robin scheduling allocates a fixed time slice to each task in a cyclic manner.

• Priority scheduling assig...read more

Determine if a given integer is an Armstrong number by checking if the sum of its digits raised to the power of the number of digits equals the number itself.

• Iterate through each digit of the number and calculate the sum of each digit raised to the power of the total number of digits.

• Compare the calculated sum with the original number to determine if it's an Armstrong number.

• Return 'YES' if the number is an Armstrong number, 'NO' otherwise.

Distribute chocolates among students to minimize the difference between the maximum and minimum chocolates.

• Sort the array of chocolates packets.

• Use sliding window technique to find the minimum difference between the maximum and minimum chocolates distributed to students.

• Consider edge cases like when the number of students is equal to the number of packets.

Calculate Pythagoras' coordinates to form a parallelogram with Euclid, Pascal, and Monte.

• Calculate the midpoint of the line segment between Euclid and Monte to get the coordinates of Pythagoras.

• Use the formula: x = x3 + (x2 - x1), y = y3 + (y2 - y1) to find Pythagoras' coordinates.

• Ensure that the coordinates of Pythagoras satisfy the conditions for forming a parallelogram.

Find the minimum number of coins needed to make up a given amount using specific denominations.

• Iterate through the available denominations in descending order

• For each denomination, calculate the maximum number of coins that can be used

• Subtract the total value of coins used from the amount until amount becomes 0

Find all possible paths for a rat in a maze from source to destination.

• Use backtracking to explore all possible paths in the maze.

• Keep track of visited cells to avoid revisiting them.

• Recursively try moving in all directions (up, down, left, right) until reaching the destination.

• Return a list of strings representing valid paths sorted in alphabetical order.

Sort a Singly Linked List based on actual values instead of absolute values.

• Traverse the linked list and store the values in an array.

• Sort the array based on actual values.

• Update the linked list with the sorted values.

Swap Kth elements in an array with given constraints.

• Create a function that takes the array, K value, and size of the array as input

• Swap the Kth element from the beginning with the Kth element from the end

• Handle edge cases like K being out of bounds or array size being less than 2

Yes, it is possible to get the accurate result from the given data.

• The coordinates (i,j,k) where metallic balls are present can be determined by finding the set elements in both matrix1 and matrix2.

• Additional data is not required as the given data is sufficient to determine the coordinates.

• The coordinates can be obtained by iterating through the elements of matrix1 and matrix2 and checking for set elements.

Given 'N' ropes of varying lengths, find the minimum cost to connect all ropes into one single rope.

• Sort the lengths of ropes in ascending order.

• Keep connecting the two shortest ropes at each step.

• Add the cost of connecting the two ropes to the total cost.

• Repeat until all ropes are connected.

• Return the total cost as the minimum cost to connect all ropes.

Design a database for a university with colleges, departments, and students. Write a query to get students with maximum votes.

• Use a relational database like MySQL or PostgreSQL

• Create tables for colleges, departments, students, and elections

• Use foreign keys to establish relationships between tables

• Add columns for election details like candidate names and vote counts

• Write a query to join tables and filter for maximum votes per department

Implement three stacks using a single array and handle insertion and deletion operations efficiently.

• Create an array to store elements for all three stacks and keep track of their respective top indices.

• For each query, check the type of operation (push or pop) and perform the necessary action.

• Handle cases where a pop operation is attempted on an empty stack by returning -1.

• Ensure the array size does not exceed the total number of queries.

• Example: For input '0 1 5', pop the to...read more

The task is to find the Kth largest element from a given list of numbers for each test case.

• Read the number of test cases 'T'

• For each test case, read the number of elements 'N' and the Kth largest number to find 'K'

• Sort the array in descending order and output the Kth element

Find the minimum cost to purchase a specific weight of oranges given the cost of different weight packets.

• Iterate through the list of costs and find the minimum cost to achieve the desired weight

• Keep track of the total cost while considering available packet weights

• Return -1 if it is not possible to buy exactly the desired weight

The problem involves determining the minimum number of umbrellas required to shelter a specific number of people based on the capacity of each umbrella.

• Iterate through the array of umbrella capacities to find the combination that covers exactly 'M' people.

• Keep track of the minimum number of umbrellas used to cover 'M' people.

• If it is not possible to cover 'M' people exactly, return -1.

• Example: For input [2, 3, 4] and M=5, the minimum number of umbrellas required is 2 (2-capac...read more

Given an array and a target sum, find pairs of elements that add up to the target sum.

• Iterate through the array and for each element, check if the complement (target sum - current element) is present in a hash set.

• If the complement is found, add the pair to the result list.

• Sort the pairs based on the first element, and if the first elements are equal, sort based on the second element.

Return a 2D list representing Pascal's triangle up to row N.

• Iterate through each row up to N, calculating each value based on the values from the previous row

• Use a nested loop to generate the triangle efficiently

• Consider edge cases like N=1 separately to return [[1]]

• Remember to handle the constraints given in the problem statement

A deadlock is a situation where two or more processes are unable to proceed because they are waiting for each other to release resources.

• Deadlocks occur when two or more processes are blocked and unable to continue executing.

• To detect a deadlock, look for circular wait, hold and wait, no preemption, and mutual exclusion.

• Examples of deadlocks include a printer that is waiting for a user to replace the paper tray, or two trains that are stuck on the same track waiting for each ...read more

The problem involves finding the number of distinct ways to climb N stairs by taking 1 or 2 steps at a time.

• Use dynamic programming to solve the problem efficiently.

• The number of ways to reach the Nth stair is the sum of the number of ways to reach the (N-1)th stair and the (N-2)th stair.

• Handle base cases for N=0 and N=1 separately.

• Consider using modulo operation to avoid overflow for large values of N.

Convert decimal numbers to octal representation.

• Iterate through each test case and use built-in functions to convert decimal to octal.

• Ensure the output is in base-8 system with digits ranging from 0 to 7.

• Handle constraints such as number of test cases and range of decimal numbers.

The task is to find the next greater element for each element in an array to its right, if no greater element exists, return -1.

• Use a stack to keep track of elements for which the next greater element is not found yet.

• Iterate through the array from right to left and update the stack accordingly.

• Pop elements from the stack until a greater element is found or the stack is empty.

Find the Kth largest element in an array of distinct positive integers.

• Sort the array in non-increasing order and return the Kth element.

• Ensure all elements in the array are distinct.

• Handle multiple test cases efficiently.

The task is to find the Lowest Common Ancestor (LCA) of two nodes in a Binary Search Tree (BST).

• Traverse the BST from the root to find the LCA of nodes P and Q.

• Compare the values of nodes P and Q with the current node's value to determine the LCA.

• If both nodes are on the same side of the current node, move to that side; otherwise, the current node is the LCA.

• Example: For input 2 3 and BST 1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1, the LCA is node 1.

Generate a series of numbers by subtracting K from N until 0 or negative, then adding K back to reach N without using loops.

• Create a recursive function to generate the series.

• Subtract K from N until N is 0 or negative, then add K back until N is reached.

• Return the series as an array of integers.

Determine maximum profit with at most K transactions by buying and selling stocks on given days.

• Iterate through the array of prices while keeping track of the maximum profit achievable with at most K transactions.

• Use dynamic programming to store the maximum profit at each day and transaction count.

• Consider buying and selling stocks at each day to calculate the maximum profit.

• Return the maximum profit achievable with at most K transactions.

The task is to identify all distinct triplets within an array that sum up to a specified number.

• Iterate through the array and use nested loops to find all possible triplets.

• Check if the sum of the triplet equals the specified number.

• Print the valid triplets or return -1 if no triplet exists.

The goal is to minimize the total cost of arranging 'N' words on each line with a maximum character limit 'M'.

• Calculate the cost of each line as the cube of extra space characters needed to reach 'M'.

• Minimize the total cost by arranging words to fit within the character limit on each line.

• Ensure each word appears fully on one line without breaking across lines.

Given an integer N, divide it into K positive parts to maximize their product.

• Divide N into K parts such that their sum equals N

• Maximize the product of the K parts

• Constraints: 1 ≤ T ≤ 11, 2 ≤ N ≤ 55

• Example: For N = 10, parts [3, 3, 4] give product 36

Detect cycles in an undirected graph with given vertices and edges.

• Use Depth First Search (DFS) to traverse the graph and detect cycles.

• Maintain a visited array to keep track of visited vertices and a parent array to keep track of the parent of each vertex.

• If while traversing, you encounter a visited vertex that is not the parent of the current vertex, then a cycle exists.

• Consider edge cases like disconnected graphs and self-loops.

The problem involves determining if a string is formed by interleaving two other strings while maintaining their order.

• Check if the length of string C is equal to the sum of the lengths of strings A and B.

• Iterate through string C and check if all characters of A and B exist in C in the correct order.

• If at any point a character in C does not match the corresponding character in A or B, return False.

• Return True if all characters of A and B are found in C in the correct order.