40+ M-Tek Engineers Interview Questions and Answers

Match the thickness of each pen with its cap and cap them accordingly.

• Sort the pens and caps by thickness.

• Match the first pen with the first cap, second pen with the second cap and so on.

• Cap the pens with their respective caps.

• If there are any leftover caps or pens, they do not have a match.

Find the minimum/maximum number of tries required to find the floor where the egg will break in a 100 floor building with 2 eggs.

• Use binary search approach to minimize the number of tries

• Start with dropping the egg from the 14th floor, then 27th, 39th, and so on

• If the first egg breaks, use the second egg to find the exact floor by checking each floor one by one

• If the first egg doesn't break, move up to the next floor and repeat the process

• The maximum number of tries is 14 if ...read more

Find minimum/maximum tries to find the floor where an egg will break in a 100 floor building with 2 eggs.

• Use binary search approach to minimize number of tries

• Start with dropping egg from 14th floor, then 27th, 39th, and so on

• If first egg breaks, use second egg to check floors below the last successful drop

• If first egg doesn't break, increase the drop interval and repeat

• Minimum tries required is 14 and maximum is 20

Match the thickness of each pen with its cap and cap them accordingly.

• Sort the pens and caps by thickness.

• Match the first pen with the first cap, second pen with the second cap and so on.

• Cap the pens with their respective caps.

• If there are any leftover caps or pens, they do not have a match.

Static function in C++ class is used to access class-level data without creating an object.

• Static functions can be called using the class name and scope resolution operator (::)

• They cannot access non-static data members of the class

• They can be used to implement utility functions that do not require access to object-specific data

• Static functions are shared among all objects of the class

Virtual functions in C++ use vtables to enable dynamic binding. Example code included.

• Virtual functions allow polymorphism in C++

• Vtables are used to maintain a list of virtual functions

• Each class with virtual functions has its own vtable

• Vtable entries are function pointers to the virtual functions

• Example code: class Shape { virtual void draw() = 0; };

• Example code: class Circle : public Shape { void draw() override { ... } };

Implement an API to return the second minimum element in a stack.

• Create a stack and a variable to store the second minimum element.

• Whenever a new element is pushed, compare it with the current second minimum and update if necessary.

• Whenever an element is popped, check if it is the current second minimum and update if necessary.

• Return the second minimum element when the secondMin() API is called.

A dictionary can be represented in memory as an array of strings. Worst case complexity of search is O(n).

• A dictionary can be represented as an array of strings where each string contains a key-value pair separated by a delimiter.

• For example, ['apple: a fruit', 'banana: a fruit', 'carrot: a vegetable']

• The worst case complexity of a search in this DS is O(n) as we may need to traverse the entire array to find the desired key-value pair.

Virtual functions in C++ are used for runtime polymorphism. Vtable is maintained to store function pointers.

• Virtual functions are declared using the virtual keyword

• Vtable is a table of function pointers maintained by the compiler

• Each class with virtual functions has its own vtable

• Vtable entries are function pointers to the virtual functions of the class

• Example code: class Shape { virtual void draw() { ... } };

• Example code: Shape* s = new Circle(); s->draw(); // calls Circle::...read more

Implement secondMin() API for a stack with push and pop operations.

• Create a second stack to keep track of the minimum values.

• Push the current minimum value to the second stack every time a new minimum is found.

• Pop the top element from the second stack when the minimum value is removed from the main stack.

• Return the second element from the top of the second stack as the second minimum value.

Static function in C++ class and its usage

• Static function belongs to the class rather than the instance of the class

• It can be called without creating an object of the class

• It is used to perform operations that do not depend on the state of the object

• To call a static function, use the class name followed by the scope resolution operator and the function name

To determine if a point is inside or outside a rectangle, compare the point's coordinates with the rectangle's boundaries.

• Compare the x-coordinate of the point with the x-coordinates of the left and right boundaries of the rectangle.

• Compare the y-coordinate of the point with the y-coordinates of the top and bottom boundaries of the rectangle.

• If the point's x-coordinate is between the left and right boundaries AND the point's y-coordinate is between the top and bottom boundari...read more

To determine the line that passes through a point and divides a rectangle into 2 equal halves, find the midpoint of the rectangle and draw a line through the midpoint and the given point.

• Find the midpoint of the rectangle by averaging the x and y coordinates of the opposite corners.

• Draw a line through the midpoint and the given point using the point-slope formula.

• Check that the line intersects the opposite sides of the rectangle at the same distance from the midpoint to ensur...read more

There are 2^24 possible combinations of 8-bit and 16-bit signed numbers.

• The scheme contains both 8-bit and 16-bit signed numbers.

• The total number of possible combinations is 2^24.

• This is because there are 2^8 possible combinations of 8-bit signed numbers and 2^16 possible combinations of 16-bit signed numbers.

• Multiplying these two values gives us 2^24 total possible combinations.

A variable can be allocated in different segments of memory.

• Global memory segment

• Stack memory segment

• Heap memory segment

• Code memory segment

Variables can be allocated in different segments of memory.

• Global variables are allocated in the data segment.

• Local variables are allocated in the stack segment.

• Dynamically allocated variables are allocated in the heap segment.

• Static variables are allocated in the data segment.

• Thread-local variables are allocated in the thread-local storage segment.

Object oriented programming is a programming paradigm that uses objects to represent and manipulate data.

• OOP focuses on creating reusable code through the use of classes and objects

• It emphasizes encapsulation, inheritance, and polymorphism

• Examples of OOP languages include Java, C++, and Python

Overloading is having multiple methods with the same name but different parameters. Overriding is having a method in a subclass with the same name and parameters as in the superclass.

• Overloading is compile-time polymorphism while overriding is runtime polymorphism.

• Overloading is used to provide different ways of calling the same method while overriding is used to provide a specific implementation of a method in a subclass.

• Overloading is achieved within the same class while ov...read more

Auto and volatile are storage classes in C language. Scopes of variables determine where they can be accessed.

• Auto variables are declared within a block and have a local scope.

• Volatile variables are used to indicate that the value of the variable may change at any time.

• Global variables have a file scope and can be accessed from any function within the file.

• Static variables have a local scope but retain their value between function calls.

• Extern variables have a global scope an...read more

Count the number of set bits in a given number's binary representation.

• Convert the number to binary representation

• Iterate through each bit and count the number of set bits

• Use bitwise AND operator to check if a bit is set or not

• Keep incrementing the count for each set bit

Object-oriented programming is a programming paradigm that uses objects to represent and manipulate data.

• It focuses on creating reusable code by organizing data and behavior into objects.

• Objects have properties (attributes) and methods (functions) that can be accessed and modified.

• Encapsulation, inheritance, and polymorphism are key concepts in object-oriented programming.

• Examples of object-oriented programming languages include Java, Python, and C++.

Overloading is having multiple methods with the same name but different parameters. Overriding is having a method in a subclass with the same name and parameters as in the superclass.

• Overloading is compile-time polymorphism while overriding is runtime polymorphism.

• Overloading is used to provide different ways of calling the same method while overriding is used to provide a specific implementation of a method in a subclass.

• Overloading is done in the same class while overriding...read more

Auto and volatile are storage classes in C programming language. Scopes of variables determine where they can be accessed.

• Auto variables are created and destroyed automatically within a block of code.

• Volatile variables are used to indicate that the value of the variable may change unexpectedly.

• Scopes of variables determine where they can be accessed. Local variables have block scope, while global variables have file scope.

• Static variables have function scope and retain their ...read more

Count the number of set bits in a given number's binary representation.

• Convert the number to binary representation using bitwise operators.

• Iterate over the binary representation and count the number of set bits.

• Alternatively, use built-in functions like bin() and count() in Python.

• The time complexity of the algorithm should be O(log n).

Programs can crash due to various reasons such as memory errors, bugs, hardware issues, etc.

• Memory errors such as accessing uninitialized memory, buffer overflows, etc.

• Bugs in the code such as infinite loops, null pointer dereferences, etc.

• Hardware issues such as power failures, overheating, etc.

• External factors such as network failures, input/output errors, etc.

• Tools like Valgrind can help detect memory errors and other issues.

Explanation of pointers with increment/decrement, address of and value at operators.

• Pointers are variables that store memory addresses.

• Increment/decrement operators change the address stored in a pointer.

• Address of operator (&) returns the memory address of a variable.

• Value at operator (*) returns the value stored at a memory address.

• Pointers can be used to manipulate data directly in memory.

Programs can crash due to various reasons such as memory errors, bugs, hardware issues, etc.

• Memory errors such as accessing uninitialized memory or freeing already freed memory

• Bugs in the code such as infinite loops or null pointer dereferences

• Hardware issues such as power failure or overheating

• Valgrind issues such as memory leaks or invalid reads/writes

• Operating system issues such as insufficient resources or conflicts with other programs

It depends on the specific use case and implementation.

• C and C++ have different strengths and weaknesses.

• C is often used for low-level programming and system-level tasks.

• C++ is often used for object-oriented programming and high-level tasks.

• The performance difference between C and C++ can be negligible or significant depending on the implementation.

• Optimizations and compiler settings can also affect performance.

• Benchmarking and profiling can help determine which language is f...read more

Find subarray with highest sum in an array of numbers.

• Use Kadane's algorithm to find maximum subarray sum

• Initialize max_so_far and max_ending_here to 0

• Iterate through the array and update max_ending_here and max_so_far

• Return the subarray with highest sum

• Example: [-2, 1, -3, 4, -1, 2, 1, -5, 4] => [4, -1, 2, 1]

I know various sorting algorithms including bubble sort, insertion sort, selection sort, merge sort, quick sort, heap sort.

• Bubble sort - repeatedly swapping adjacent elements if they are in wrong order

• Insertion sort - inserting each element in its proper place in a sorted subarray

• Selection sort - selecting the smallest element and swapping it with the first element

• Merge sort - dividing the array into two halves, sorting them and then merging them

• Quick sort - selecting a pivot...read more

I know various sorting algorithms including bubble sort, insertion sort, selection sort, merge sort, quick sort, heap sort.

• Bubble sort - repeatedly swapping adjacent elements if they are in wrong order

• Insertion sort - iteratively inserting elements into a sorted sub-list

• Selection sort - repeatedly selecting the smallest element and swapping it with the current element

• Merge sort - recursively dividing the array into two halves, sorting them and merging them

• Quick sort - recursi...read more

It depends on the specific use case and implementation.

• C and C++ have different performance characteristics.

• C++ has additional features that may impact performance.

• Optimizations can be applied to both languages.

• Benchmarking is necessary to determine which is faster in a specific scenario.

Find subarray with highest sum in an array of numbers.

• Use Kadane's algorithm to find maximum subarray sum

• Initialize max_so_far and max_ending_here to 0

• Iterate through the array and update max_ending_here and max_so_far

• Return the subarray with highest sum

• Example: [-2, 1, -3, 4, -1, 2, 1, -5, 4] => [4, -1, 2, 1]

Locate sum of 2 numbers in a linear array (sorted/unsorted) and their complexities.

• For unsorted array, use nested loops to compare each element with every other element until the sum is found. Complexity: O(n^2)

• For sorted array, use two pointers approach starting from both ends of the array and move towards each other until the sum is found. Complexity: O(n)

• Hash table can also be used for unsorted array to reduce complexity to O(n).

• Binary search can also be used for sorted ar...read more

C++ is an extension of C with object-oriented programming features.

• C++ supports classes and objects while C does not.

• C++ has better support for polymorphism and inheritance.

• C++ has a larger standard library than C.

• C++ allows function overloading while C does not.

• C++ supports exception handling while C does not.

C++ is an extension of C with object-oriented programming features.

• C++ supports classes and objects while C does not.

• C++ has better support for function overloading and templates.

• C++ has a standard library that includes many useful functions.

• C++ allows for both procedural and object-oriented programming.

• C++ is generally considered more complex than C.

Static binding is resolved at compile-time while dynamic binding is resolved at runtime.

• Static binding is also known as early binding while dynamic binding is also known as late binding.

• Static binding is faster than dynamic binding as it is resolved at compile-time.

• Dynamic binding is more flexible than static binding as it allows for polymorphism.

• An example of static binding is method overloading while an example of dynamic binding is method overriding.

Static binding is done at compile-time while dynamic binding is done at runtime.

• Static binding is also known as early binding while dynamic binding is also known as late binding.

• Static binding is faster than dynamic binding as it is done at compile-time.

• Dynamic binding is more flexible than static binding as it allows for polymorphism.

• An example of static binding is function overloading while an example of dynamic binding is virtual functions in C++.

Allocate a 2-D array using C/C++

• Use the 'new' operator to allocate memory for the array

• Specify the number of rows and columns in the array

• Access elements using array indexing

The height and diameter of a tree are important measurements for forestry and landscaping purposes.

• Height can be measured using a clinometer or by using trigonometry and a measuring tape.

• Diameter can be measured at breast height (4.5 feet above ground) using a diameter tape or by measuring circumference and dividing by pi.

• These measurements are important for determining the health and growth of a tree, as well as for planning and managing forests and landscapes.

• For example, a...read more

The height and diameter of a tree are important measurements in forestry and arboriculture.

• Height is typically measured from the base of the tree to the highest point of the crown.

• Diameter is measured at breast height, which is 4.5 feet above the ground.

• These measurements are used to determine the age, health, and value of a tree.

• For example, a tall tree with a narrow diameter may indicate poor growth, while a shorter tree with a wide diameter may indicate healthy growth.

• In f...read more

Allocate a 2-D array using C/C++

• Use the 'new' keyword to allocate memory dynamically

• Specify the number of rows and columns in the array

• Access elements using array indexing

UNION in C is a data type that allows storing different data types in the same memory location.

• UNION is declared using the 'union' keyword.

• It can be used to save memory by sharing the same memory location for different data types.

• Accessing the members of a union can be done using the dot operator or the arrow operator.

• Example: union myUnion { int i; float f; };

• Example: myUnion.u.i = 10; myUnion.u.f = 3.14;

Cell padding is the space between the content of a cell and its border in a table.

• Cell padding can be set using CSS or HTML attributes.

• It affects the appearance of the table and can improve readability.

• Padding can be set for individual cells or for the entire table.

• Example:

• Example: td { padding: 10px; }

UNION in C is a data type that allows storing different data types in the same memory location.

• UNION is declared using the 'union' keyword.

• It can be used to save memory by sharing the same memory location for different data types.

• Accessing the value of a union member that was not recently assigned results in undefined behavior.

• Example: union myUnion { int i; float f; };

• Example: myUnion u; u.i = 10; printf("%d %f", u.i, u.f);

Cell padding is the space between the content of a cell and its border in a table.

• Cell padding can be set using CSS or HTML attributes.

• It affects the appearance of the table and can improve readability.

• Padding can be set individually for each cell or for the entire table.

• Example:

References in C++ allow a variable to refer to another variable's memory address.

• References are declared using the '&' symbol.

• They are often used as function parameters to avoid copying large objects.

• References cannot be null and cannot be reassigned to refer to a different object.

• They are commonly used in operator overloading to modify the original object.

• Example: int x = 5; int& y = x; y++; // x is now 6.

• Example: void swap(int& a, int& b) { int temp = a; a = b; b = temp; }