Thomson Reuters Senior Systems Engineer Interview Questions and Answers

Find an odd occurring number among even occurring numbers.

• Use XOR operation to cancel out even occurring numbers and get the odd occurring number.

• Iterate through the array and XOR each element with the result variable.

• The final result will be the odd occurring number.

Print the spiral order of a binary tree and matrix.

• For binary tree, use level order traversal and alternate direction for each level.

• For matrix, use four pointers to traverse in spiral order.

• Example for binary tree: 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9

• Example for matrix: 1 2 3 4 -> 8 7 6 5 -> 9 10 11 12 -> 16 15 14 13

Finding pairs in an array with a given sum.

• Iterate through the array and for each element, check if the difference between the given sum and the element exists in the array.

• Use a hash table to store the elements of the array and their indices for faster lookup.

• If there are multiple pairs with the same sum, return any one of them.

• If no pair is found, return null or an empty array.

Find total number of k element with given avg in an array in minimum time complexity.

• Use sliding window technique to traverse the array in O(n) time complexity.

• Maintain a sum variable to keep track of the sum of elements in the window.

• If the sum of elements in the window is equal to k times the given avg, increment the count.

• Move the window by subtracting the first element and adding the next element in the array.

Printing non-boundary elements of a binary tree

• Traverse the tree in any order (preorder, inorder, postorder)

• Check if the current node is not a boundary node (not the first or last node in its level)

• If it is not a boundary node, print its value

• Recursively traverse its left and right subtrees

A friend function is a non-member function that has access to the private and protected members of a class.

• Declared inside the class but defined outside the class scope

• Can access private and protected members of the class

• Not a member of the class but has access to its private members

• Used to allow external functions to access and modify private data of a class

• Can be declared as a friend in another class

atoi function converts a string to an integer in C.

• The function takes a string as input and returns an integer.

• Leading white spaces are ignored.

• If the string contains non-numeric characters, the function stops conversion and returns the converted value.

• The function returns 0 if the input string is not a valid integer.

• Example: atoi('123') returns 123.

A program to print star pattern

• Use nested loops to print the pattern

• The outer loop controls the number of rows

• The inner loop controls the number of stars to be printed in each row

• Use print() or println() function to print the stars

Run time polymorphism is the ability of a program to determine the object type at runtime and call the appropriate method.

• It is achieved through virtual functions and dynamic binding.

• Allows for more flexible and extensible code.

• Example: a base class Animal with virtual function makeSound() and derived classes Dog and Cat that override makeSound().

• At runtime, if an Animal pointer points to a Dog object, calling makeSoun

Right outer join is a type of join operation that returns all the rows from the right table and the matching rows from the left table.

• Right outer join is denoted by the RIGHT JOIN keyword in SQL.

• It is used to combine rows from two tables based on a related column.

• In the result set, unmatched rows from the right table will have NULL values for the columns of the left table.

• A real-world scenario for using a right outer j...read more

Refrential integrity ensures that relationships between tables in a database remain consistent.

• It is a database concept that ensures that foreign key values in one table match the primary key values in another table.

• It prevents orphaned records in a database.

• It maintains data consistency and accuracy.

• For example, if a customer record is deleted, all related orders for that customer should also be deleted.

• It is enforced...read more

Primary key uniquely identifies a record in a table, while Unique key ensures uniqueness of a column.

• Primary key can't have null values, Unique key can have one null value

• A table can have only one Primary key, but multiple Unique keys

• Primary key is automatically indexed, Unique key is not necessarily indexed

Triggers are database objects that are automatically executed in response to certain events.

• Triggers can be used to enforce business rules, audit changes, or replicate data.

• There are two types of triggers: DML triggers and DDL triggers.

• DML triggers are fired in response to DML statements (INSERT, UPDATE, DELETE).

• DDL triggers are fired in response to DDL statements (CREATE, ALTER, DROP).

Swapping two character variables without using third

• Use XOR operator to swap two variables without using third variable

• Assign the XOR of both variables to the first variable

• Assign the XOR of the first variable and second variable to the second variable

I have been actively involved in various extra curricular activities such as volunteering, sports, and leadership roles.

• Volunteered at local animal shelter every weekend

• Captain of the soccer team in high school

• Organized charity events for underprivileged children

A generic swap function swaps two values of any data type.

• The function should take two parameters of any data type.

• Use a temporary variable to store the value of one parameter.

• Assign the value of the second parameter to the first parameter.

• Assign the value of the temporary variable to the second parameter.

Search for an element in a rotated sorted linked list.

• Find the pivot point where the list is rotated.

• Divide the list into two sublists based on the pivot point.

• Perform binary search on the appropriate sublist.

• Handle edge cases such as empty list and list with only one element.

Search an element in a rotated sorted array

• Find the pivot point where the array is rotated

• Divide the array into two sub-arrays based on pivot point

• Perform binary search on the appropriate sub-array

• Repeat until element is found or sub-array size is 1

Find 5 missing numbers in an array of size 95 containing numbers in range 1 to 100.

• Create a boolean array of size 100 and mark the present numbers

• Iterate through the boolean array and find the missing numbers

• Alternatively, use a HashSet to store the present numbers and find the missing ones

Given a Sudoku board, find possible numbers for an empty cell.

• Iterate through empty cells and check possible numbers using row, column, and box constraints.

• Use a set to keep track of possible numbers for each empty cell.

• Return the set of possible numbers for the given empty cell.

Find integer average of 4 unsigned integers without typecasting

• Add all the integers and divide by 4

• Use bit shifting to divide by 4

• Handle overflow by using long long data type

• Use unsigned int data type for input

Code to identify 32 bit or 64 bit architecture of a processor

• Check if the operating system is 32 bit or 64 bit

• If OS is 32 bit, processor is 32 bit

• If OS is 64 bit, check if processor supports 64 bit architecture

• Use CPUID instruction to check if processor supports 64 bit architecture

Convert binary number to base 64 integer

• Divide the binary number into groups of 6 bits

• Convert each group of 6 bits to decimal

• Map the decimal value to the corresponding base 64 character

• Concatenate the base 64 characters to form the final integer