20+ Trion Infotech Interview Questions and Answers

The task is to find the subarray with the maximum sum in a given array.

• Iterate through the array and keep track of the current sum and maximum sum seen so far.

• If the current sum becomes negative, reset it to 0 as it won't contribute to the maximum sum.

• Compare the maximum sum with the sum of the current subarray to update the result.

• Handle cases where all elements are negative by returning the maximum element in the array.

• Consider edge cases like empty array or array with only...read more

Find the minimum time required to rot all fresh oranges in a grid.

• Use Breadth First Search (BFS) to simulate the rotting process

• Track the time taken to rot all oranges and return -1 if any fresh oranges remain

• Handle edge cases like no fresh oranges or all oranges already rotten

• Consider using a queue to efficiently process adjacent oranges

Find the node where two linked lists merge, return -1 if no merging occurs.

• Traverse both lists to find their lengths and the difference in lengths

• Move the pointer of the longer list by the difference in lengths

• Traverse both lists simultaneously until they meet at the merging point

Reverse a singly linked list by altering the links between nodes.

• Iterate through the linked list and reverse the links between nodes

• Use three pointers to keep track of the current, previous, and next nodes

• Update the links between nodes to reverse the list

• Return the head of the reversed linked list

Merge K sorted arrays into one sorted array in ascending order.

• Iterate through all arrays/lists and merge them into one sorted array using a priority queue or merge sort algorithm.

• Ensure to handle edge cases like empty arrays/lists or arrays/lists with different sizes.

• Time complexity can be optimized by using a min-heap or priority queue to efficiently merge the arrays/lists.

Print the left view of a binary tree given in level order form.

• Traverse the tree level by level and print the first node of each level (leftmost node).

• Use a queue to perform level order traversal.

• Keep track of the current level and print the first node encountered at each level.

Find the maximum path sum between two leaf nodes in a binary tree.

• Traverse the tree to find the maximum path sum between two leaf nodes.

• Keep track of the maximum sum found so far.

• Consider all possible paths between leaf nodes.

• Handle cases where the tree has only a single leaf node.

• Implement a recursive function to calculate the maximum path sum.

Find the majority element in an array, return -1 if no majority element exists.

• Iterate through the array and keep track of the count of each element using a hashmap.

• Check if any element's count is greater than floor(N/2) to determine the majority element.

• Return the majority element or -1 if no majority element exists.

Find the N-th node from the end of a Singly Linked List of integers.

• Traverse the list to find the length L of the list.

• Calculate the position of the N-th node from the beginning as L - N + 1.

• Traverse the list again to reach the calculated position and return the node's value.

Find the Lowest Common Ancestor (LCA) of two nodes in a binary tree.

• Traverse the binary tree to find the paths from the root to nodes X and Y.

• Compare the paths to find the last common node, which is the LCA.

• Handle cases where one node is an ancestor of the other or when one node is the LCA itself.

Reverse words in a string while handling leading/trailing spaces and multiple spaces between words.

• Split the input string by spaces to get individual words

• Reverse the list of words

• Join the reversed words with a single space in between

• Handle leading/trailing spaces by stripping them before and after reversing

Assign subjects to friends to minimize maximum workload, find minimum time for most loaded friend.

• Sort subjects in descending order

• Assign subjects to friends one by one until all subjects are assigned

• The maximum workload will be the sum of problems assigned to the friend with the most problems

• Return the maximum workload as the minimum time required

Find the total sum of all root to leaf paths in a binary tree formed by concatenating node values.

• Traverse the binary tree from root to leaf nodes, keeping track of the current path sum

• Add the current path sum to the total sum when reaching a leaf node

• Use modulo (10^9 + 7) to handle large outputs

Implement a function to find any topological sorting of a Directed Acyclic Graph (DAG).

• Use Kahn's algorithm to find a topological sort of the DAG.

• Start by finding all vertices with in-degree 0 and add them to the result array.

• Remove these vertices and their outgoing edges from the graph, then repeat the process.

• Continue until all vertices are added to the result array.

• Return the result array as the topological sort of the DAG.

Grammar in compiler design defines the syntax and structure of a programming language.

• Grammar specifies the rules for forming valid statements in a programming language.

• It consists of a set of production rules that define how valid programs can be constructed.

• There are different types of grammars such as context-free grammar, regular grammar, etc.

• Example: In C programming language, the grammar specifies that a for loop should have a specific syntax like 'for(initialization; c...read more

Code to split an array of integers into two subarrays with equal sum.

• Iterate through the array and calculate the total sum.

• Divide the sum by 2 to get the target sum for each subarray.

• Use dynamic programming to find a subset of the array that adds up to the target sum.

• Return the two subarrays.

• Example: [1, 2, 3, 4, 5, 6] -> [1, 2, 3, 6], [4, 5]

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

Implementing a binary search tree and its traversal methods.

• Start by defining a Node class with left and right child pointers.

• Implement insert() method to add nodes to the tree.

• Implement inorder(), preorder(), and postorder() traversal methods.

• Implement search() method to find a node in the tree.

• Implement delete() method to remove a node from the tree.

• Consider edge cases like empty tree, duplicate nodes, etc.

NP problems are decision problems that can be verified in polynomial time, while NP-Hard problems are at least as hard as the hardest problems in NP.

• NP problems can be verified in polynomial time but not necessarily solved in polynomial time.

• NP-Hard problems are at least as hard as the hardest problems in NP, but may not be in NP themselves.

• Examples of NP problems include the subset sum problem and the traveling salesman problem.

• Examples of NP-Hard problems include the travel...read more

A token in compiler design is a basic unit of syntax that the compiler can understand and process.

• Tokens are the smallest units of a program that are meaningful to the compiler.

• Examples of tokens include keywords, identifiers, operators, and punctuation symbols.

• Tokens are generated by the lexical analysis phase of the compiler.

• Tokens are used by the parser to build the abstract syntax tree of the program.

Find unique characters in a window of k size in a string.

• Use a sliding window approach.

• Maintain a hash table to keep track of character frequency.

• Remove characters from hash table as the window slides.

Convert given no to corresponding excel no.

• Excel no starts from 1 and goes up to 16384

• Excel no is calculated using column and row numbers

• For example, 1 corresponds to A, 27 corresponds to AA, 28 corresponds to AB, and so on

A regular language is a language that can be recognized by a finite automaton.

• Regular languages can be described by regular expressions.

• Regular languages are closed under union, concatenation, and Kleene star operations.

• Examples of regular languages include the set of all strings over an alphabet that contain an even number of 'a's.

To find the second highest salary from employees table and traverse a binary tree in pre-order, in-order, and post-order.

• To find the second highest salary, you can use a subquery or window function like ROW_NUMBER() or DENSE_RANK().

• For pre-order traversal, visit the root node first, then recursively do a pre-order traversal of the left subtree, followed by the right subtree.

• For in-order traversal, recursively do an in-order traversal of the left subtree, visit the root node, ...read more