20+ Ficode Technologies Interview Questions and Answers

Find the duplicate number in an array of integers from 0 to N-2.

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

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

The task is to find the frequency of each character from 'a' to 'z' in a given string.

• Create an array of size 26 to store the frequency of each character from 'a' to 'z'.

• Iterate through the string and increment the count of the corresponding character in the array.

• Print the array of frequencies as the output for each test case.

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

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

• Swap elements based on the values encountered to sort the array in-place.

• Time complexity should be O(N) and space complexity should be O(1).

The N Queens Problem involves finding all possible placements of N queens on an N x N chessboard without threatening each other.

• Use backtracking algorithm to explore all possible configurations.

• Keep track of rows, columns, and diagonals to ensure queens do not threaten each other.

• Generate all valid configurations and print them out.

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

Reverse the order of elements in an array and display the reversed array.

• Iterate through the array from both ends and swap the elements until the middle is reached.

• Use a temporary variable to store the element being swapped.

• Print the reversed array after all elements have been swapped.

The task is to determine the maximum profit that can be achieved by performing up to two buy-and-sell transactions on a given set of stock prices.

• Iterate through the array of stock prices and calculate the maximum profit that can be achieved by buying and selling at different points.

• Keep track of the maximum profit after the first transaction and the maximum profit overall by considering different combinations of buy and sell points.

• Return the maximum profit obtained after co...read more

Find pairs of elements in an array that sum up to a given value, sorted in a specific order.

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

• Keep track of pairs in a hash set to avoid duplicates.

• Sort the pairs based on the criteria mentioned in the question.

• Return the sorted list of pairs.

Given an integer, find the final single-digit value after summing its digits iteratively.

• Iteratively sum the digits of the given integer until the result is a single-digit number

• Output the final single-digit integer for each test case

• Handle multiple test cases efficiently

Detect if a given linked list is circular by checking if it forms a closed loop.

• Traverse the linked list using two pointers, one moving at double the speed of the other.

• If the two pointers meet at any point, the linked list is circular.

• If the faster pointer reaches the end of the list (NULL), the linked list is not circular.

Sort an array using pancake flips and return the sequence of flips made.

• Iterate through the array and find the position of the maximum element in each iteration.

• Perform pancake flips to move the maximum element to the correct position.

• Continue this process until the array is sorted.

• Return the sequence of positions from where flips were made.

Check if a given number is a Fibonacci number or not.

• Iterate through the Fibonacci sequence until you find a number greater than or equal to the given number.

• Check if the given number matches the Fibonacci number found in the sequence.

• If the number matches, output 'YES'; otherwise, output 'NO'.

Reverse the letters of a string while keeping non-alphabet characters in their original position.

• Iterate through the string and store the non-alphabet characters in their original positions

• Reverse the letters using two pointers technique

• Combine the reversed letters with the non-alphabet characters to get the final reversed string

Calculate the Nth Fibonacci number efficiently using dynamic programming.

• Use dynamic programming to store and reuse previously calculated Fibonacci numbers.

• Start with base cases F(1) and F(2) as 1, then calculate subsequent Fibonacci numbers.

• Optimize the solution to avoid redundant calculations by storing intermediate results.

• Time complexity can be reduced to O(N) using dynamic programming.

• Example: For N = 5, the 5th Fibonacci number is 5.

Find duplicates in an array of integers within a specified range.

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

• Return elements with count greater than 1 as duplicates.

• Time complexity can be optimized to O(N) using a set to store duplicates.

• Example: For input [0, 3, 1, 2, 3], output should be [3].

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization is a technique used to organize data in a database efficiently.

• Third Normal Form (3NF) is a level of normalization that ensures that data is stored in a way that prevents certain types of data anomalies.

• In 3NF, every non-prime attribute is fully functionally dependent on the primary key.

• For example, if we have a table 'Employees' with columns 'EmployeeID...read more

SQL query to find the second highest salary from a table

• Use the MAX() function to find the highest salary

• Use the NOT IN operator to exclude the highest salary from the results

• Order the results in descending order and limit the query to return only the second row

Count the occurrence of each element in an array of strings

• Iterate through the array and use a hashmap to store the count of each element

• If element already exists in the hashmap, increment its count by 1

• Return the hashmap with element counts

Sort a vector based on another vector

• Use std::sort with a custom comparator function

• The comparator function should compare the indices of the elements in the second vector

• The first vector should be sorted based on the order of the indices in the second vector

The minimum number of swaps needed to group all ones together in an array of 0s and 1s.

• Iterate through the array to count the total number of ones.

• Use a sliding window of size equal to the total number of ones to find the window with the minimum number of zeros.

• Calculate the number of swaps needed to move all ones to that window.

Zigzag traversal of binary tree involves alternating the direction of traversal at each level.

• Use a queue to perform level order traversal of the binary tree.

• For each level, alternate between adding nodes to the result list from left to right and right to left.

• Continue this process until all levels have been traversed.