Cadence Design Systems Softwaretest Engineer Interview Questions and Answers

To check if a directed graph is cyclic or not

• Use Depth First Search (DFS) algorithm to traverse the graph

• Maintain a visited set to keep track of visited nodes

• Maintain a recursion stack to keep track of nodes in the current DFS traversal

• If a node is visited and is already in the recursion stack, then the graph is cyclic

• If DFS traversal completes without finding a cycle, then the graph is acyclic

Return a random byte from a stream of bytes with equal probability.

• Create a variable to store the count of bytes read

• Create a variable to store the current random byte

• For each byte read, generate a random number between 0 and the count of bytes read

• If the random number is 0, store the current byte as the random byte

• Return the random byte

Check if a binary tree is a binary search tree or not.

• Traverse the tree in-order and check if the values are in ascending order.

• For each node, check if its value is greater than the maximum value of its left subtree and less than the minimum value of its right subtree.

• Use recursion to check if all nodes in the tree satisfy the above condition.

Algorithm to find Nth-to-Last element in a singly linked list of unknown length

• Traverse the list and maintain two pointers, one at the beginning and one at Nth node from beginning

• Move both pointers simultaneously until the second pointer reaches the end of the list

• The first pointer will be pointing to the Nth-to-Last element

• If N=0, return the last element

• Parse the list only once

Print all possible permutations of an array of integers

• Use recursion to swap elements and generate permutations

• Start with the first element and swap it with each subsequent element

• Repeat the process for the remaining elements

• Stop when all elements have been swapped with the first element

• Print each permutation as it is generated

Design a stack that prints the minimum element pushed in O(1)

• Use two stacks, one for storing elements and another for storing minimums

• When pushing an element, compare it with the top of minimum stack and push the smaller one

• When popping an element, pop from both stacks

• To get the minimum element, just return the top of minimum stack

To find the starting point of a loop in a linked list, use Floyd's cycle-finding algorithm.

• Use two pointers, one moving at twice the speed of the other.

• When they meet, move one pointer to the head of the list and keep the other at the meeting point.

• Move both pointers one step at a time until they meet again, which is the starting point of the loop.

To find a number in a matrix where all rows and columns are sorted non-decreasingly. Complexity of the solution.

• Use binary search to find the number in each row and column

• Start from the top-right corner or bottom-left corner to optimize search

• Time complexity: O(m log n) or O(n log m) depending on the starting corner

Code to print * in five consecutive lines

• Use a loop to iterate five times

• Inside the loop, print a string containing a single * character

Code to calculate number of bounces a ball goes through until it comes to rest.

• Use a loop to simulate the bounces until the ball stops bouncing

• Calculate the height of each bounce using the given formula

• Keep track of the number of bounces in a counter variable

The best and less time consuming way to calculate factorial of a number is using iterative approach.

• Iteratively multiply the number with all the numbers from 1 to the given number

• Start with a result variable initialized to 1

• Multiply the result with each number in the range

• Return the final result

Code to find factorial using function recursion

• Define a function that takes an integer as input

• Check if the input is 0 or 1, return 1 in that case

• Otherwise, call the function recursively with input-1 and multiply it with the input

The question is about finding the minimum steps to reach from a source string to a destination string using three operations.

• BFS and DFS are graph traversal techniques that can be used to solve this problem.

• BFS is typically used when finding the shortest path or exploring all possible paths in a graph.

• DFS is useful when searching for a specific path or exploring deeply into a graph.

• In this case, BFS can be used to find...read more

Need more context. What needs to be done with the large rectangle?

• What are the dimensions of the rectangle?

• Is it a 2D or 3D object?

• What is the context of the problem?

• Are there any constraints or limitations?

• What tools or programming languages can be used?

Derive a formula to determine how many smaller rectangles fit into a bigger rectangle given their dimensions.

• Calculate the number of times the smaller rectangle can fit into the bigger rectangle horizontally and vertically

• Divide the width of the bigger rectangle by the width of the smaller rectangle to get the horizontal count

• Divide the height of the bigger rectangle by the height of the smaller rectangle to get the ve...read more

At least 4 points are required to draw a rectangle.

• A rectangle has 4 sides and 4 corners, so at least 4 points are needed to define those corners.

• The points must be arranged in a specific order to form a closed shape with 4 sides.

• Additional points can be used to add details or modify the shape of the rectangle.

• The number of points required may vary depending on the software or tool used to draw the rectangle.

Answering how to calculate new coordinates of a scaled rectangle and providing a program for it.

• To calculate new coordinates, multiply the original coordinates by the scaling factor

• Scaling factor can be calculated by dividing the new length/breadth by the original length/breadth

• Program can take input of original coordinates, scaling factor, and output new coordinates

• Example: Original coordinates: (0,0), (0,5), (5,5), (...read more