10+ Video Home & Electronic Centre Interview Questions and Answers

Count the number of islands in a 2D matrix of 1s and 0s.

• Use Depth First Search (DFS) or Breadth First Search (BFS) to traverse the matrix and identify connected groups of 1s.

• Maintain a visited array to keep track of visited cells to avoid counting the same island multiple times.

• Increment the island count each time a new island is encountered during traversal.

• Consider edge cases such as when the matrix is empty or when all cells are water (0s).

Implement a queue using two stacks with enqueue and dequeue operations.

• Use two stacks to simulate a queue - one for enqueue and one for dequeue.

• For enqueue operation, push elements onto the enqueue stack.

• For dequeue operation, if dequeue stack is empty, pop all elements from enqueue stack and push onto dequeue stack.

• Return true for successful enqueue and -1 for empty dequeue.

• Example: Enqueue 10, enqueue 20, dequeue (returns 10), enqueue 30, dequeue (returns 20).

Find the minimum total cost to paint all houses such that no two adjacent houses have the same color.

• Use dynamic programming to keep track of the minimum cost of painting each house with each color while ensuring no two adjacent houses have the same color.

• At each house, calculate the minimum cost of painting it with each color based on the previous house's colors.

• Keep updating the minimum cost for each color at each house until reaching the last house.

• Return the minimum cost ...read more

The task is to find the in-order traversal of a given binary tree.

• Implement a recursive function to perform in-order traversal of the binary tree

• Start from the left subtree, then visit the root node, and finally visit the right subtree

• Use an array to store the values of the nodes in the in-order traversal

Given a sorted matrix, find the position of a target integer in the 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

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

Find the contiguous subarray with the maximum product of elements in an array.

• Iterate through the array and keep track of the maximum and minimum product ending at each index.

• Update the maximum product by taking the maximum of current element, current element * previous maximum, and current element * previous minimum.

• Update the minimum product by taking the minimum of current element, current element * previous maximum, and current element * previous minimum.

• Return the maximu...read more

Divide a given string into N equal parts and return the divided strings as an array of strings.

• Calculate the length of each part by dividing the length of the string by N.

• Iterate through the string and extract substrings of the calculated length.

• Return the array of divided strings.

• Handle cases where it is not possible to divide the string into N equal parts.

The task is to find the total number of ways to paint fences using 2 colors such that at most 2 adjacent fences have the same color.

• Use dynamic programming to solve the problem

• Create a 2D array to store the number of ways to paint the fences

• Initialize the base cases for the first two fences

• Use recurrence relation to calculate the number of ways for the remaining fences

• Return the result modulo 10^9 + 7

Linear Probing in Hashing is a technique to resolve collisions in hash tables by linearly searching for the next available slot.

• Implement a function that takes an array of non-negative integers and returns the corresponding hash table using linear probing.

• Use the given hash function H(X) = X mod N to map elements to indices in the hash table.

• Handle collisions by linearly probing for the next available slot in the hash table.

• Ensure the constraints are met: 1 <= T <= 10, 1 <= N...read more

The task is to extract and print the internet resource address from a given string.

• The internet resource address has a specific format: ://.ru[/]

• The can be either 'http' or 'ftp'

• The is a non-empty string of lowercase English letters

• The may or may not be present, and if present, it is a non-empty string of lowercase English letters

• If is not present, the address has either two '/' characters (before the domain) or three (an extra one in front of the context)

The problem is to determine if it is possible to color the vertices of an undirected graph using at most M colors such that no two adjacent vertices have the same color.

• The input consists of the number of test cases, the number of vertices and colors, and the adjacency matrix of the graph.

• For each test case, check if it is possible to assign colors to the vertices such that no adjacent vertices have the same color.

• Use a backtracking or graph coloring algorithm to solve the pr...read more

The task is to find the minimum number of multiplication operations required to multiply a series of matrices together.

• Use dynamic programming to solve the problem efficiently.

• Create a 2D array to store the minimum number of operations needed to multiply matrices.

• Iterate through different combinations of matrices to find the optimal solution.

• Consider the dimensions of matrices and their compatibility for multiplication.

• Calculate the minimum number of operations by considering...read more

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

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

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

• Handle edge cases like duplicates and negative numbers appropriately.

• Return pairs in any order as (a, b) or (b, a).

Convert a Roman numeral string to its integer equivalent.

• Create a mapping of Roman numeral symbols to their integer values.

• Iterate through the input string and add the corresponding integer values.

• Handle cases where a smaller value precedes a larger value (e.g., IV = 4).

To join multiple models in a DBMS, use SQL JOIN statements based on common keys.

• Identify common keys between the models

• Use SQL JOIN statements (INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN) to combine the models based on the common keys

• Specify the columns to be selected in the SELECT statement