10+ TCS Interview Questions and Answers

Printing the right view of a tree using recursion and level order traversal.

• Recursively traverse the right subtree first and then the left subtree.

• For level order traversal, use a queue to store nodes at each level.

• Print the rightmost node at each level.

• Example: For tree 1-2-3-4-5, the right view is 1-2-4-5.

A binary tree with 4 internal nodes has 5 leaf nodes.

• A binary tree with n internal nodes has n+1 leaf nodes.

• A leaf node is a node with no children.

• Count the number of leaf nodes to find the answer.

Given preorder and postorder traversal, find inorder traversal of a binary tree.

• The last element of postorder traversal is the root of the tree

• Find the root in preorder traversal and divide the tree into left and right subtrees

• Recursively find the inorder traversal of left and right subtrees

• Combine the inorder traversal of left subtree, root, and inorder traversal of right subtree

The number of swaps required to sort an array using bubblesort

• Bubble sort compares adjacent elements and swaps them if they are in the wrong order

• Count the number of swaps required to sort the given array

• The given array requires 19 swaps to be sorted using bubblesort

Interview questions for Analyst II position on SQL, Tableau, and Guesstimate

• SQL: finding duplicates, order of execution, rank and dense rank, running total

• Tableau: live vs extract, scatter plot and box plot, IDR and outliers formula

• Guesstimate: estimating number of flights taking off from an airport in a day

Outliers can be found using statistical methods such as z-score, IQR, or using machine learning algorithms like isolation forest.

• Calculate z-score for each data point and consider points with z-score greater than 3 or less than -3 as outliers.

• Use interquartile range (IQR) to identify outliers. Points outside the range of Q1 - 1.5*IQR and Q3 + 1.5*IQR are considered outliers.

• Isolation Forest is a machine learning algorithm that can be used to identify outliers in a dataset.

• Vis...read more

Naive Bayes assumes independence between features, hence 'naive'.

• Naive Bayes assumes all features are independent of each other, which is often not true in real-world data.

• Despite its simplifying assumption, Naive Bayes is still widely used in text classification and spam filtering.

• The 'naive' assumption allows for fast and efficient classification, especially with large datasets.

To evaluate your approach, I would estimate the number of cars passing through a busy intersection in a day.

• Identify the average number of cars passing through the intersection per minute

• Calculate the total number of minutes in a day

• Multiply the average cars per minute by total minutes in a day to get an estimate

Execution of SQL involves writing and running queries to retrieve, manipulate, and manage data in a database.

• Write SQL queries to retrieve specific data from database tables

• Use SQL functions and operators to manipulate data

• Execute SQL statements to update or delete records in database

• Manage database schema by creating, altering, or dropping tables

• Optimize SQL queries for better performance

Recursive problem involving finding the factorial of a number.

• Implement a recursive function to calculate the factorial of a number.

• Base case: if n is 0 or 1, return 1.

• Recursive case: return n * factorial(n-1).

Parking lot design involves layout, capacity, accessibility, and efficiency.

• Consider the layout of the parking lot to maximize space and ease of navigation.

• Include designated spots for different types of vehicles (e.g. compact, electric, handicap).

• Implement efficient traffic flow patterns to reduce congestion and improve safety.

• Incorporate technology such as sensors or apps for real-time parking availability updates.