100+ Technical Trainee Interview Questions and Answers

Find the minimum cost to reach a destination in a matrix with specified rules.

• Use Breadth First Search (BFS) algorithm to explore all possible paths from the starting point to the destination.

• Keep track of the cost incurred at each cell and update it as you move through the matrix.

• Return the minimum cost to reach the destination or -1 if it is unreachable.

• Consider edge cases such as when the starting point is the destination or when the destination is blocked.

Given an array where all elements appear twice except two, find and return the two unique elements.

• Use XOR operation to find the XOR of all elements in the array, which will give the XOR of the two unique elements.

• Find the rightmost set bit in the XOR result to divide the array into two groups based on that bit.

• XOR each group separately to find the two unique elements.

• Example: For input [2, 4, 6, 8, 4, 2], XOR result is 6^8=14. Rightmost set bit is at position 1. Group 1: [6,...read more

Find the maximum elements for each subarray of size 'K' in a given array of non-negative integers.

• Iterate through the array and maintain a deque to store the indices of elements in decreasing order.

• Pop elements from the deque if they are out of the current window of size 'K'.

• The front of the deque will always have the index of the maximum element for the current window.

Given a singly linked list with integers separated by '0', merge nodes between '0's into a single node with sum of included nodes.

• Traverse the linked list and keep track of sum between zeroes

• Merge nodes between zeroes by updating the sum in the merged node

• Update the linked list by removing the nodes between zeroes

• Handle edge cases like list starting and ending with '0'

Count the total number of derangements possible for a set of 'N' elements.

• A derangement is a permutation where no element appears in its original position.

• Use the formula for derangements: !n = n! * (1 - 1/1! + 1/2! - 1/3! + ... + (-1)^n/n!)

• Return the answer modulo (10^9 + 7) to handle large results.

Convert a given array representing a min-heap into a max-heap.

• Iterate through the array and swap parent nodes with their children to convert min-heap to max-heap.

• Maintain the heap property by comparing parent with its children and swapping if necessary.

• Ensure the final array satisfies the max-heap property where parent nodes are greater than their children.

Count the number of palindrome words in a given string.

• Split the string into words using whitespace as delimiter.

• Check each word if it is a palindrome by comparing it with its reverse.

• Increment a counter for each palindrome word found.

• Output the total count of palindrome words for each test case.

The task is to transform an integer array into a max binary heap structure.

• Create a max heap from the given array by rearranging elements.

• Check if each internal node has a value greater than or equal to its children.

• Output '1' if the transformed array represents a max-heap, else output '0'.

Swap two integers 'a' and 'b' and output the swapped values.

• Create a temporary variable to store one of the integers before swapping

• Assign the value of 'a' to 'b' and the temporary variable to 'a'

• Output the swapped values as 'b' followed by 'a'

Implement Merge Sort algorithm to sort a sequence of numbers in non-descending order.

• Divide the input array into two halves recursively until each array has only one element.

• Merge the sorted halves to produce a completely sorted array.

• Ensure the implementation handles the constraints specified in the problem statement.

• Example: For input [3, 1, 4, 1, 5], the output should be [1, 1, 3, 4, 5].

Check if second string can be formed using characters from the first string.

• Iterate through each character in STR2 and check if it exists in STR1.

• Use a hashmap to store the frequency of characters in STR1 for efficient lookup.

• Return 'YES' if all characters in STR2 are found in STR1, otherwise return 'NO'.

Detect and remove loop in a singly linked list in place with O(n) time complexity and O(1) space complexity.

• Use Floyd's Cycle Detection Algorithm to identify the loop in the linked list.

• Once the loop is detected, use two pointers to find the start of the loop.

• Adjust the pointers to remove the loop and return the modified linked list.

Calculate the total amount of rainwater that can be trapped within given elevation map.

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

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

• Sum up the trapped water above each bar to get the total trapped water for the elevation map.

The task is to find the distance of the closest points among an array of N points in the plane.

• Calculate the distance between each pair of points using the given formula

• Keep track of the minimum distance found so far

• Return the minimum distance

The problem involves determining the number of distinct ways to climb from the 0th to the Nth stair by climbing one or two steps at a time.

• Use dynamic programming to solve this problem efficiently.

• The number of ways to reach the Nth stair can be calculated by adding the number of ways to reach the (N-1)th stair and the (N-2)th stair.

• Consider base cases where N=0 and N=1 separately.

• Handle large values of N by using modulo arithmetic.

• Example: For N=3, the number of distinct way...read more

Convert a sorted linked list into a Balanced Binary Search Tree (BST) using the same data values.

• Create a function to convert the linked list to a BST by recursively dividing the list into halves

• Maintain a pointer to the middle element of the list as the root of the BST

• Recursively set the left and right children of the root using the left and right halves of the list

• Perform level order traversal to output the values of the BST nodes in the required format

Find the minimum number of dice throws required to reach the last cell on a 'Snake and Ladder' board.

• Create a graph representation of the board with snakes and ladders as edges.

• Use Breadth First Search (BFS) to find the shortest path from the starting cell to the last cell.

• Keep track of visited cells and the number of dice throws at each cell.

• Handle cases where the last cell is unreachable by returning -1.

• Consider the special cases where the last cell is reached through a lad...read more

The task is to output the Spiral Order traversal of a binary tree given in level order.

• Implement a function that returns the spiral order traversal as a list

• Traverse the binary tree in a spiral order alternating between left to right and right to left

• Use a queue to keep track of nodes at each level

• Handle null nodes represented by -1 in the input

Distribute N candies among K people in Sanyam's order of likeness, incrementing distribution by K each round until all candies are distributed.

• Distribute candies starting from 1st friend, incrementing by K each round

• If remaining candies are fewer than what a friend is supposed to receive, stop distribution

• Output the number of candies each friend ends up with at the end of distribution

The task is to find all pairs of elements in an array that add up to a given 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.

• Print the pairs found or (-1, -1) if no pair is found.

Calculate uneaten carrots after rabbits jump based on their unique factors.

• Iterate through each rabbit's jumping factor and mark the carrots they land on as eaten

• Calculate the remaining uneaten carrots by counting the ones not marked as eaten

• Consider using a data structure like an array to keep track of eaten carrots efficiently

Reverse a singly linked list by altering the links between nodes.

• Iterate through the linked list and reverse the links between nodes

• Use three pointers to keep track of the current, previous, and next nodes

• Update the links between nodes to reverse the list

• Return the head of the reversed linked list

Reverse a given stack of integers using recursion without extra space or loop constructs.

• 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.

• Ensure to handle base cases for empty stack or single element stack.

• Example: If the input stack is [1, 2, 3], after reversal it should be [3, 2, 1].

Implement a function to compress a string by replacing consecutive characters with the character followed by the count of repetitions.

• Iterate through the input string and keep track of consecutive characters and their counts.

• Replace consecutive characters with the character followed by the count of repetitions if count is greater than 1.

• Return the compressed string for each test case.

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 the maximum sum of a simple path between any two nodes in a binary tree.

• Use a recursive approach to traverse the binary tree and calculate the maximum sum path.

• Keep track of the maximum sum path found so far while traversing the tree.

• Consider negative values in the path sum calculation to handle cases where the path can start and end at different nodes.

• Handle cases where the path can go through the root node or not.

The goal is to determine the frequency of each word in a given string.

• Split the input string into individual words

• Create a dictionary to store word frequencies

• Iterate through the words and update the frequency count in the dictionary

• Print each unique word and its frequency