7000+ Software Developer Interview Questions and Answers

Find the length of the smallest subarray in a given array whose sum exceeds a specified value.

• Iterate through the array while keeping track of the sum of the current subarray.

• Use two pointers to maintain a sliding window approach to find the smallest subarray.

• Update the minimum length of the subarray whenever the sum exceeds the specified value.

• Return the length of the smallest subarray found.

• Handle cases where no subarray exists with sum exceeding the specified value.

The task is to find the total number of ways to make change for a specified value using given denominations.

• Use dynamic programming to solve this problem efficiently.

• Create a 1D array to store the number of ways to make change for each value from 0 to the target value.

• Iterate through the denominations and update the array based on the current denomination.

• The final answer will be the value at the target index of the array.

The task is to find the cheapest price from the given source to destination with up to K stops.

• Read the number of test cases

• For each test case, read the number of stations and trains

• Read the details of each train (source, destination, ticket price)

• Read the source station, destination station, and maximum number of stops

• Implement a graph data structure to represent the stations and trains

• Use a modified version of Dijkstra's algorithm to find the cheapest price with up to K sto...read more

Linear search algorithm to find the first occurrence of an integer in an array.

• Iterate through the array and compare each element with the target integer.

• Return the index if the target integer is found, else return -1.

• Time complexity is O(N) where N is the size of the array.

Reverse a singly linked list of integers and return the head of the reversed linked list.

• Iterate through the linked list and reverse the pointers to point to the previous node instead of the next node.

• Use three pointers to keep track of the current, previous, and next nodes while reversing the linked list.

• Update the head of the reversed linked list as the last node encountered during the reversal process.

This question asks to find the position of a target integer in a row-wise and column-wise sorted matrix.

• Iterate through each row and column of the matrix

• Compare the target integer with the current element

• If the target integer is found, return the position as {i, j}

• If the target integer is not found, return {-1, -1}

Distribute chocolates among students to minimize the difference between the largest and smallest number of chocolates.

• Sort the array of chocolates.

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

• Return the minimum difference as the output.

Count the total number of good subsets in an array where elements can be rearranged to divide the next element.

• Iterate through all possible subsets of the array.

• Check if each subset is a good subset by rearranging elements to divide the next element.

• Count the number of good subsets and return the total count.

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

• Iterate through the array and for each element, check if the target minus the element exists in a hash set.

• If it exists, add the pair to the result. If not, add the element to the hash set.

• Handle cases where the same element is used twice to form a pair.

• Return (-1, -1) if no pair is 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.

The task is to determine the minimum number of towers needed to stack cubes in a specific order.

• Iterate through the array of cubes and maintain a stack to keep track of towers.

• For each cube, check if it can be placed on an existing tower or start a new one.

• Update the stack based on the cube's size and count the number of towers needed.

• Return the minimum number of towers required.

• Example: For input N = 3, ARR = [3, 2, 1], the output should be 1.

Construct the largest number by concatenating positive integers in the array exactly once.

• Sort the array of integers in a way that the concatenation of the numbers forms the largest possible number.

• Use a custom comparator function to sort the numbers based on their concatenated values.

• Join the sorted array elements to form the final largest number.

Count occurrences of a digit in a given range.

• Iterate through the range [A, B] and count occurrences of digit K.

• Convert integers to strings for easier digit comparison.

• Handle edge cases like when A or B is equal to K.

• Optimize by considering the position of K in the range.

Check if Ninja can create two teams with equal members given an integer N and its divisors.

• Iterate through all divisors of N and assign members to the first or second team based on whether the divisor is even or odd.

• Keep track of the total members in each team and check if they are equal at the end.

• Return true if the total members in both teams are equal, false otherwise.

Determine the minimum time required to paint all boards with given constraints.

• Use binary search to find the minimum and maximum possible time to paint all boards.

• Iterate through the boards and assign them to painters based on the time constraints.

• Calculate the total time taken to paint all boards with the assigned painters.

Remove duplicate occurrences of characters in a given string of lowercase English letters.

• Use a hash set to keep track of characters already seen.

• Iterate through the string and add each character to the result if it's not in the hash set.

• Return the result string after removing duplicates.

Find the minimum time required to rot all fresh oranges adjacent to rotten oranges.

• Create a queue to store the coordinates of rotten oranges and perform BFS to rot adjacent fresh oranges.

• Track the time taken to rot all fresh oranges and return -1 if not all fresh oranges can be rotten.

• Update the grid with the new state of oranges after each second.

• Handle edge cases such as empty grid or no fresh oranges present.

• Example: For the given grid, the minimum time required is 4 secon...read more

Count the number of structurally unique binary trees that can be constructed with given Dragon Balls.

• Use dynamic programming to solve this problem efficiently.

• The number of structurally unique binary trees can be calculated using Catalan numbers.

• For each test case, calculate the number of structurally unique binary trees modulo 10^9 + 7.

• Return the count of unique binary trees for each test case.

Find the maximum number of chocolates that can be collected by two friends moving in a grid.

• Start from the top-left and top-right corners, move diagonally down to collect chocolates

• Calculate the total chocolates collected by each friend and sum them up for the final result

• Consider all possible paths for both friends to maximize the total chocolates collected

Check if a given integer is a member of the Fibonacci series.

• Implement a function to check if the given number is a perfect square.

• Check if 5*N^2 + 4 or 5*N^2 - 4 is a perfect square to determine Fibonacci membership.

• Return true if the number is a perfect square of 5*N^2 + 4 or 5*N^2 - 4, otherwise false.

Find the minimum cost to make all elements of an array equal by changing them to a common value.

• Calculate the median of the array and find the sum of absolute differences between each element and the median.

• Sort the array and find the median element, then calculate the sum of absolute differences between each element and the median.

• If the array has an even number of elements, consider the average of the two middle elements as the median.

Find the minimum time to travel from a starting point to a destination point using direct movement and wormholes.

• Calculate the time taken for direct movement from source to destination.

• Consider using each wormhole to see if it reduces the total travel time.

• Choose the path with the minimum total time to reach the destination.

Find the minimum number of moves required to collect all keys in a grid starting from a specified point.

• Use breadth-first search (BFS) to explore all possible paths from the starting point to collect keys.

• Keep track of keys collected, locks encountered, and the number of moves taken in each path.

• Avoid revisiting cells, and consider the movement rules while traversing the grid.

• Return the minimum number of moves to collect all keys, or -1 if it is impossible.

Determine total number of valid shopping combinations within budget

• Iterate through all possible combinations of items from each array

• Check if the total cost of the combination is within the budget

• Return the count of valid combinations

Find the minimum number of rotations required to unlock a briefcase with a given target code, considering dead-end codes.

• Iterate through all possible combinations of rotations to find the shortest path to the target code.

• Use a queue to efficiently explore all possible combinations.

• If the target code is a dead-end code, return -1 as it is not feasible to unlock the briefcase.

Generate all possible combinations of balanced parentheses for a given number of pairs.

• Use recursion to generate all possible combinations of balanced parentheses.

• Keep track of the number of open and close parentheses used in each combination.

• Terminate recursion when the number of open and close parentheses used equals the given number of pairs.

The problem is to find the intersection of two sorted arrays.

• Use two pointers to iterate through the arrays.

• Compare the elements at the current pointers and move the pointers accordingly.

• If the elements are equal, add it to the intersection array and move both pointers.

• If the element in the first array is smaller, move the first pointer.

• If the element in the second array is smaller, move the second pointer.

• Repeat until one of the pointers reaches the end of its array.

• Return t...read more

Calculate the minimum number of left shift operations needed to achieve the longest common prefix between two strings.

• Apply left shift operations to string B to find the longest common prefix with string A

• Count the number of left shifts needed to achieve the longest common prefix

• Return the minimum number of left shift operations for each test case

Given N meetings with start and end times, find the maximum number of meetings that can be organized in a single room without overlap.

• Sort the meetings based on their end times.

• Iterate through the sorted meetings and select the next meeting that does not overlap with the current meeting.

• Keep track of the selected meetings and return their indices in the order they are organized.

The minimum number of operations needed to make all elements of the array equal by performing addition, multiplication, subtraction, or division on any element.

• Iterate through the array and find the maximum and minimum values

• Calculate the difference between the maximum and minimum values

• Check if the difference is divisible by the length of the array

• If divisible, return the difference divided by the length

• If not divisible, return the difference divided by the length plus one

The task is to check if there exist two unique elements in the given BST such that their sum is equal to the given target 'K'.

• Traverse the BST in-order and store the elements in a sorted array

• Use two pointers, one at the beginning and one at the end of the array

• Check if the sum of the elements at the two pointers is equal to the target 'K'

• If the sum is less than 'K', move the left pointer to the right

• If the sum is greater than 'K', move the right pointer to the left

• Repeat the...read more

Count distinct pairs in an array whose sum equals a given target.

• Use two pointers approach to iterate through the array and find pairs with sum equal to target.

• Keep track of visited pairs to avoid counting duplicates.

• Return -1 if no such pair exists with the given target.

Implement a function to find the shortest distance between two vertices in a weighted, undirected graph.

• Use Dijkstra's algorithm to find the shortest path between the given vertices.

• Create a graph data structure to represent the weighted, undirected graph.

• Handle cases where no path exists between the given vertices by returning -1.

• Optimize the algorithm to handle multiple queries efficiently.

• Consider edge cases such as when the same vertex is given for both 'u' and 'v'.

Find the smallest substring in S containing all characters in X.

• Use a sliding window approach to find the smallest window in S containing all characters in X.

• Keep track of the characters in X using a hashmap.

• Slide the window to the right until all characters in X are found, then shrink the window from the left to find the smallest window.

The task is to construct a binary tree using the given inorder and preorder traversals.

• Use the preorder traversal to determine the root of the binary tree

• Use the inorder traversal to determine the left and right subtrees of the root

• Recursively construct the left and right subtrees

• Return the root node of the constructed binary tree

Given an array of integers and an integer K, determine if there exist two distinct indices i and j such that ARR[i] == ARR[j] and | i - j | <= K.

• Iterate through the array and keep track of the indices of each element using a hashmap.

• Check if the current element already exists in the hashmap within a distance of K.

• Return 'Yes' if a pair of such indices exists, otherwise return 'No'.

The task is to delete the middle node of a singly linked list of integers.

• If the linked list is empty or has only one node, there is no middle node to delete.

• To delete the middle node, we need to find the middle node and update the pointers of the previous and next nodes.

• To find the middle node in one traversal, we can use two pointers - a slow pointer and a fast pointer.

• The slow pointer moves one node at a time, while the fast pointer moves two nodes at a time.

• When the fast ...read more

Identify the duplicate integer in an array containing numbers between 1 and N-1.

• Iterate through the array and keep track of the frequency of each element using a hashmap.

• Return the element with a frequency greater than 1 as the duplicate integer.

• Time complexity can be optimized to O(N) using Floyd's Tortoise and Hare algorithm.

• Example: For input [1, 2, 3, 4, 4], the output should be 4.

Implement a function to find the index of a given integer in a singly linked list.

• Traverse the linked list while keeping track of the index of each element.

• Compare each element with the target integer 'N'.

• Return the index if 'N' is found, otherwise return -1.

• Handle cases where the list is empty or 'N' is not found.

• Consider the constraints on the number of test cases and the length of the linked list.

Find the maximum path sum between two leaf nodes in a binary tree.

• Traverse the tree to find the maximum path sum between two leaf nodes

• Consider both cases where the path passes through the root and where it doesn't

• Use recursion to calculate the sum of paths from each leaf node to the root

The task is to find the maximum sum of node values of any subtree that is a Binary Search Tree(BST).

• Traverse the binary tree in a bottom-up manner

• For each node, check if it forms a BST and calculate the sum of its subtree

• Keep track of the maximum sum encountered so far

• Return the maximum sum

Find the minimum cost selection of roads to travel to every state in a country.

• Create a graph representation of the states and roads with their costs.

• Use a minimum spanning tree algorithm like Kruskal's or Prim's to find the optimal roads.

• Select 'N' - 1 roads with the lowest costs to cover all states.

• Return the selected roads and their costs as output.

The challenge involves splitting an array into sub-arrays to minimize cost based on unique elements and repetitions.

• Iterate through the array and keep track of unique elements and repetitions

• Calculate cost for each sub-array based on the rules provided

• Sum up the costs for all sub-arrays to get the total minimum cost

Design a seating arrangement for a high-security meeting with specific table assignments for security personnel and guests.

• Create a loop to iterate through each row from 1 to N.

• Assign tables on either end of each row to security personnel.

• For rows with only one table, assign it to security personnel.

• Display the seating arrangement with the number of people at each table.

• Example: For 4 rows, the output pattern is 1, 11, 121, 1221.

Calculate uneaten carrots by rabbits with specific jumping factors.

• Iterate through each carrot and check if any rabbit jumps on it.

• Use the jumping factors to determine which carrots will be eaten.

• Subtract the eaten carrots from the total to get the uneaten carrots.

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