1500+ System Engineer Interview Questions and Answers

Determine the winner of an election between two candidates based on the influence of supporters on neutral voters.

• Iterate through the string to count the number of supporters for each candidate.

• Simulate the movement of supporters of A and B to influence neutral voters.

• Compare the total number of supporters for A and B to determine the election winner.

• Handle cases where there is a tie by declaring it as a Coalition.

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.

• Define a recursive function to calculate the number of ways to reach each stair based on the number of ways to reach the previous two stairs.

• Consider base cases for 0th and 1st stair.

• Keep track of the number of ways modulo 10^9+7 to avoid overflow issues.

Find the row index with the most number of full parking spaces in a given matrix.

• Iterate through each row of the matrix and count the number of 1's in each row.

• Keep track of the row index with the maximum count of 1's.

• Return the index of the row with the maximum count of 1's.

The greatest common divisor (GCD) of two numbers is the largest positive integer that divides both numbers without leaving a remainder.

• Use Euclidean algorithm to find GCD efficiently

• GCD(X, Y) = GCD(Y, X % Y)

• Repeat until Y becomes 0, then X is the GCD

Count the number of unique strings in an array by allowing swapping of characters at odd and even indices.

• Iterate through each string in the array and check if it can be transformed into another string by swapping characters at odd and even indices.

• Keep track of unique strings using a set data structure.

• Return the size of the set as the number of unique strings.

Given a string and a list of words, determine if each word in the list is present in the string and return a boolean array indicating their presence.

• Iterate through each word in the word list and check if it is present in the string.

• Use a boolean array to store the presence of each word in the string.

• Consider case sensitivity when checking for word presence.

• Do not use built-in string-matching methods.

• Return the boolean array without printing it.

Choose at most N/2 elements from an array A of N elements and find XOR of all the chosen elements.

• Choose the N/2 largest elements to maximize the XOR value.

• Use a priority queue to efficiently select the largest elements.

• If N is small, brute force all possible combinations of N/2 elements.

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.

• If the complement exists, add the pair to the result list.

• Sort the result list based on the criteria mentioned in the question.

• Return the sorted list of pairs.

Check if a given string is identical to its mirror reflection.

• Iterate through the string and compare characters from start and end simultaneously.

• If any characters don't match, return 'NO'.

• If all characters match, return 'YES'.

OOPs concepts are the fundamental principles of Object-Oriented Programming.

• Encapsulation: Binding data and functions together in a single unit.

• Inheritance: Acquiring properties and behavior of a parent class by a child class.

• Polymorphism: Ability of an object to take many forms.

• Abstraction: Hiding the implementation details and showing only the necessary information.

• Example: A car is an object that encapsulates data like speed, fuel, and functions like start, stop, and accel...read more

Generate all possible non-empty subsets of an array of distinct integers.

• Use recursion to generate subsets by including or excluding each element in the array.

• Maintain a current subset and add it to the result when reaching the end of the array.

• Ensure elements within each subset are in increasing order.

• Handle the input and output format as specified in the question.

• Consider edge cases like empty array or array with only one element.

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 while traversing the list to reverse it

• Return the head of the reversed linked list

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

• Use Floyd's Cycle Detection Algorithm to determine if there is a cycle in the linked list.

• Maintain two pointers, one moving at twice the speed of the other, if they meet at some point, there is a cycle.

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

The problem involves finding the number of twin pairs in an array based on a specific condition.

• Iterate through the array and check for each pair of indices if they form a twin pair based on the given condition

• Keep track of the count of twin pairs found

• Return the total count of twin pairs for each test case

To achieve NlogN complexity in the worst case, we can implement the randomized version of quicksort algorithm.

• Randomly select a pivot element to reduce the chances of worst-case scenarios.

• Implement a hybrid sorting algorithm like Introsort which switches to heap sort when the recursion depth exceeds a certain limit.

• Use median-of-three partitioning to select a good pivot element for better performance.

• Optimize the algorithm by using insertion sort for small subarrays to reduce...read more

Implement a Trie data structure supporting insertion and search operations for words.

• Create a TrieNode class with a dictionary to store children nodes.

• Implement insert(word) by iterating through each character of the word and creating nodes if necessary.

• Implement search(word) by traversing the Trie and checking for the presence of the word.

• Use a boolean flag in TrieNode to mark the end of a word.

• Handle Type 1 and Type 2 queries accordingly in the main program.

The task is to distribute candies to students based on their performance while minimizing the total candies distributed.

• Create an array to store the minimum candies required for each student.

• Iterate through the students' ratings array to determine the minimum candies needed based on the given criteria.

• Consider the ratings of adjacent students to decide the number of candies to distribute.

• Calculate the total candies required by summing up the values in the array.

• Implement a fu...read more

Implement the merge sort algorithm to sort a singly linked list of integers.

• Divide the linked list into two halves recursively

• Merge the sorted halves using the merge() function

• Implement the merge() function to merge two sorted subarrays

• Ensure the constraints are met for input elements

• Return the sorted linked list for each test case

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

Yes, the 0/1 Knapsack Problem can be solved using dynamic programming with a space complexity of not more than O(W).

• Use a 1D array to store the maximum value that can be stolen for each weight capacity from 0 to W.

• Iterate through each item and update the array based on whether including the item would increase the total value.

• The final element of the array will contain the maximum value that can be stolen within the weight capacity of the knapsack.

Print a binary pattern based on input integer N in a specific format.

• Iterate from N to 1 and print N - i + 1 numbers alternatively as 1 or 0 in each line

• Handle the test cases by reading the number of test cases first

• Follow the given constraints for input and output format

Group anagrams in a list of strings and return them as separate groups.

• Iterate through the list of strings and sort each string to find anagrams.

• Use a hashmap to group anagrams together based on their sorted versions.

• Return the grouped anagrams as separate lists of strings.

The task is to determine the maximum number of unique vehicle registrations given the number of districts, letter ranges, and digit ranges.

• Parse the input for each test case: number of districts, letter ranges, and digit ranges.

• Calculate the total number of unique registrations based on the given constraints.

• Output the maximum number of unique vehicle registrations for each test case.

• Consider the ranges of alphabets and digits to determine the total combinations possible.

• Ensu...read more

The task is to determine the number of distinct islands in a grid of 0s and 1s connected horizontally, vertically, or diagonally.

• Iterate through the grid and for each '1' encountered, perform a depth-first search to mark all connected '1's as visited.

• Use a set to store the unique shapes of islands encountered during the traversal.

• Return the size of the set as the total number of distinct islands in the grid.

Integrity rules in a DBMS ensure data accuracy, consistency, and reliability.

• Constraints like primary key, foreign key, unique key enforce data integrity

• Referential integrity ensures relationships between tables are maintained

• Entity integrity ensures each row has a unique identifier

• Domain integrity enforces valid data types and values

• Check constraints validate data before insertion or update

INNER JOIN returns only the matching rows between two tables, while OUTER JOIN returns all rows from one table and matching rows from the other.

• INNER JOIN is used to retrieve rows from both tables that have matching values based on a specified condition.

• OUTER JOIN is used to retrieve all rows from one table and only matching rows from the other table.

• Types of OUTER JOIN include LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• Example: INNER JOIN would return a list of students who have r...read more

Generate all valid parentheses combinations for a given number of pairs.

• Use backtracking to generate all possible combinations of parentheses.

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

• Add '(' if there are remaining open parentheses, and add ')' if there are remaining close parentheses.

• Stop when the length of the generated string is equal to 2*N.