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
You're given string ‘STR’ consisting solely of “{“, “}”, “(“, “)”, “[“ and “]” . Determine whether the parentheses are balanced.
Input Format:
The first line contains an Integer &...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
Answered by CodingNinjas
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Q2. Group Anagrams
You have been given an array/list of strings 'inputStr'. You are supposed to return the strings as groups of anagrams such that strings belonging to a particular group are anagrams o...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
Given an array "prices". In "prices" the ith element is the price of the stock on the ith day. Your task is to find maximum profit at the end of the ith day. Yo...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
You are given two strings BEGIN and END and an array of strings DICT. Your task is to find the length of the shortest transformation sequence from BEGIN to END such that in every transformation...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
Answered by CodingNinjas
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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. Ninjas's Robot
Ninja has a robot that can move in an infinite number line. The robot starts at position 0, with speed = +1. The robot moves automatically according to the sequence of instructions “A” (Acc...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
Answered by CodingNinjas
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