Tracxn Full Stack Software Developer Interview Questions and Answers

Round duration - 60 minutes
Round difficulty - Medium

Algorithm and Data Structures. MCQ based on dbms, html, css, js, sql, oops, program output.

Q1. 
Valid Parentheses Problem Statement
Given a string 'STR' consisting solely of the characters “{”, “}”, “(”, “)”, “[” and “]”, determine if the parentheses are balanced.
Input:
The first line contains an...read more
Ans. Valid Parenthesis
Make use of the stack. Traverse the string and push the current character in the stack if it is an opening brace else pop from the stack If it is the corresponding starting brace for current closing brace then move to the next character of the string otherwise return false.
 
If after complete traversal if the stack is empty then the string is balanced else it is not balanced.
 
Pseudo Code:
• Decla...read more
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Q2. 
Group Anagrams Problem Statement
Given an array or list of strings called inputStr, your task is to return the strings grouped as anagrams. Each group should contain strings that are anagrams of one anoth...read more
Ans. Categorize by Count
The key idea behind this approach is that we can transform each string into a string representing the character count. We will use an array “count”, of size 26 such that each element of the array represents the number of a’s, b’s, c’s and so on… We will be using these frequencies to create a string, delimited by ‘#’ characters, that we will use as a key for our HashMap.
 
For example :
str=”abbccc”...read more
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Round duration - 60 minutes
Round difficulty - Medium

Algorithm and Data Structures. Sql queries insert and update commands.

Q1. 
Buy and Sell Stock - III Problem Statement
Given an array prices where the i^th element represents the price of a stock on the i^th day, your task is to determine the maximum profit that can be achieved at ...read more
Ans. Brute Force
The basic idea is that, try all possible transactions, means move to every index and try to perform one transaction before the current index and one after the current index. For all the possibilities choose maximum.
 
• ‘ans = 0’, to store answers as maximum profit.
• Iterate a loop ‘i’ from ‘0’ to ‘n - 2’.
• For every ‘i’, find the best transaction on the left side of right, which means iterate a loop ‘j’ from ‘...read more
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Q2. 
Word Ladder Problem Statement
Given two strings, BEGIN and END, along with an array of strings DICT, determine the length of the shortest transformation sequence from BEGIN to END. Each transformation inv...read more
Ans. Using BFS
The idea is to use BFS traversal of the graph because considering an edge between any two adjacent words(words that will have a difference of only one alphabet) after that you just have to find the shortest between the start word and the target word and that can be done using BFS.  
  
Here is the algorithm: 
  
1. As the BFS procedure goes start to form the "BEGIN " word, add it to...read more
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Round duration - 45 minutes
Round difficulty - Medium

Some questions related to html and css. What are the various selector in css. SQL queries on how to use group by and having. Difference between truncate and delete.

Q1. 
Problem: Ninja's Robot
The Ninja has a robot which navigates an infinite number line starting at position 0 with an initial speed of +1. The robot follows a set of instructions which includes ‘A’ (Acceler...read more
Ans.  Breadth-First Search
The basic idea is to use modified Breadth-First Search (BFS) here.  We can keep track of all the possible positions of the robot after ‘N’ instructions (N = 0, 1, 2, 3, 4, ...) and return the smallest ‘N’ such that the ‘TARGET’ position is reached
 
The steps are as follows:
1. Initialize an integer variable ‘N’:= 0.
2. Create a queue of list/array ‘STATE’  Each element in the queue has an arr...read more
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