60+ Ray International Llc Oman Interview Questions and Answers

Q1. Nth Term of Geometric Progression (GP) Series

Determine the Nth term of a geometric progression (GP) series given the first term, common ratio, and the term number.

Explanation:

The general form of a GP series ...read more

Q2. Dice Throw Problem Statement

You are provided with D dice, each having F faces numbered 1 to F, inclusive. Your task is to determine the number of possible ways to roll the dice such that the sum of the face-up...read more

Q3. Mean, Median, Mode Calculation

You are given an array 'ARR' consisting of 'N' integers. Your task is to calculate the three statistical measures for the given array:

1. Mean - Implement the function mean() to cal...read more

Q4. Distinct Subsequences of a String

Given a string S of length N that may contain duplicate alphabets, your task is to compute the count of distinct subsequences of this string.

Example:

Input:

S = "deed"

Output:...read more

Q5. Median of Two Sorted Arrays

Given two sorted arrays A and B of sizes N and M, find the median of the merged array formed by combining arrays A and B. If the total number of elements, N + M, is even, the median ...read more

Q6. Arithmetic Expression Evaluation Problem Statement

You are provided with a string expression consisting of characters '+', '-', '*', '/', '(', ')' and digits '0' to '9', representing an arithmetic expression in...read more

Q7. Identical Trees Problem Statement

Given two binary trees with 'N' and 'M' nodes respectively, determine if the two trees are identical. Return true if they are identical, otherwise return false.

Input:

The firs...read more

Q8. Minimum Subarray with Required Sum Problem Statement

Given an array of positive integers ARR and an integer X, determine the minimum length subarray where the sum of its elements is strictly greater than X.

Not...read more

Q9. Longest Palindromic Subsequence Problem Statement

Ninja receives a PS5 from Santa, locked in a safe with a password. The password is the length of the longest palindromic subsequence in the given string SECRETC...read more

Q10. Delete Kth Node from End of Linked List

This problem requires you to delete the Kth node from the end of a given singly linked list with N nodes containing integer data.

You are asked to efficiently remove this...read more

Q11. Reverse a Linked List Problem Statement

Given a singly linked list of integers, your task is to return the head of the reversed linked list.

Example:

Input:

The given linked list is 1 -> 2 -> 3 -> 4-> NULL.

Out...read more

Q12. Ways To Make Coin Change

Given an infinite supply of coins of varying denominations, determine the total number of ways to make change for a specified value using these coins. If it's not possible to make the c...read more

Q13. Pair Sum Problem Statement

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.

Note:

Each pa...read more

Q14. Maximum Product Subarray Problem Statement

Given an array of integers, determine the contiguous subarray that produces the maximum product of its elements.

Explanation:

A subarray can be derived from the origin...read more

Q15. Swap Numbers Without Temporary Variable

Your task is to interchange the values of two numbers given as variables 'X' and 'Y' without using a temporary variable or any additional variable.

Explanation:

You need ...read more

Q16. Connect Nodes at the Same Level

Given a binary tree where each node has at most two children, your task is to connect all adjacent nodes at the same level. You should populate each node's 'next' pointer to its ...read more

Q17. Minimum Number of Platforms Problem

Your task is to determine the minimum number of platforms required at a railway station so that no train has to wait.

Explanation:

Given two arrays:

• AT - representing the ar...read more

Q18. Maximum Subarray Sum Problem Statement

Given an array arr of length N consisting of integers, find the sum of the subarray (including empty subarray) with the maximum sum among all subarrays.

Explanation:

A sub...read more

Q19. Longest Common Prefix After Rotation

You are given two strings 'A' and 'B'. While string 'A' is constant, you may apply any number of left shift operations to string 'B'.

Explanation:

Your task is to calculate ...read more

Q20. Minimum Steps for a Knight to Reach Target

Given a square chessboard of size 'N x N', determine the minimum number of moves a Knight requires to reach a specified target position from its initial position.

Expl...read more

Q21. Longest Palindromic Substring Problem Statement

You are provided with a string STR of length N. The goal is to identify the longest palindromic substring within this string. In cases where multiple palindromic ...read more

Q22. Rotate Matrix by 90 Degrees Problem Statement

Given a square matrix 'MATRIX' of non-negative integers, rotate the matrix by 90 degrees in an anti-clockwise direction using only constant extra space.

Input:

The ...read more

Q23. Minimum Operations Problem Statement

You are given an array 'ARR' of size 'N' consisting of positive integers. Your task is to determine the minimum number of operations required to make all elements in the arr...read more

Q24. N Queens Problem

Given an integer N, find all possible placements of N queens on an N x N chessboard such that no two queens threaten each other.

Explanation:

A queen can attack another queen if they are in the...read more

Q25. Travelling Salesman Problem

Given a list of cities numbered from 0 to N-1 and a matrix DISTANCE consisting of 'N' rows and 'N' columns, representing the distances between each pair of cities, find the shortest ...read more

Q26. Sort Stack Problem Statement

You are given a stack S. Your task is to sort the stack recursively in descending order.

Constraints:

• Looping through the stack is not allowed.
• Return the stack sorted in descendin...read more

Q27. Trapping Rain Water Problem Statement

You are given a long type array/list ARR of size N, representing an elevation map. The value ARR[i] denotes the elevation of the ith bar. Your task is to determine the tota...read more

Q28. Validate BST Problem Statement

Given a binary tree with N nodes, determine whether the tree is a Binary Search Tree (BST). If it is a BST, return true; otherwise, return false.

A binary search tree (BST) is a b...read more

Q29. Problem Statement: Sibling Nodes

You are provided with a Binary Tree consisting of 'N' nodes, where each node holds an integer value. Your objective is to identify and list all nodes that do not possess a sibli...read more

Q30. Total Number of BSTs Using Array Elements as Root Node

You are given a sequence array 'ARR' of 'N' integers. For each ARR[i] where 0 <= 'i' < 'N', your task is to find the number of Binary Search Trees (BST) po...read more

Q31. Find All Triplets with Zero Sum

Given an array Arr consisting of N integers, find all distinct triplets in the array that sum up to zero.

Explanation:

An array is said to have a triplet {Arr[i], Arr[j], Arr[k]}...read more

Q32. Problem: Sort an Array of 0s, 1s, and 2s

Given an array/list ARR consisting of integers where each element is either 0, 1, or 2, your task is to sort this array in increasing order.

Input:

The input starts with...read more

Q33. Spiral Matrix Problem Statement

You are given a N x M matrix of integers. Your task is to return the spiral path of the matrix elements.

Input

The first line contains an integer 'T' which denotes the number of ...read more

Q34. Smallest Window Problem Statement

Given two strings S and X containing random characters, the task is to find the smallest substring in S which contains all the characters present in X.

Input:

The first line co...read more

Q35. Total Area of Overlapping Rectangles Problem Statement

Determine the total area covered by two given rectangles on a 2-D coordinate plane, which may have an overlapping area.

Input:

The first line contains an i...read more

Q36. Find the Largest Common Ancestor Problem

Given a binary search tree and two distinct nodes within it, the task is to determine their largest common ancestor. This ancestor is defined as the common ancestor with...read more

Q37. LCA of Binary Tree Problem Statement

You are given a binary tree of distinct integers, along with two nodes, ‘X’ and ‘Y’. Your task is to determine the Lowest Common Ancestor (LCA) of ‘X’ and ‘Y’.

The LCA of tw...read more

Q38. Mirror String Problem Statement

Given a string S containing only uppercase English characters, determine if S is identical to its reflection in the mirror.

Example:

Input:

S = "AMAMA"

Output:

YES

Explanation:

T...read more

Q39. Cycle Detection in a Singly Linked List

Determine if a given singly linked list of integers forms a cycle or not.

A cycle in a linked list occurs when a node's next points back to a previous node in the list. T...read more

Q40. Angle Calculation Between Clock Hands

Given a specific time in hours and minutes, your task is to calculate the smallest possible angle between the hour hand and the minute hand of a clock.

Example:

Input:

T = ...read more

Q41. Quadratic Equation Root Finder

Given three integers A, B, and C representing the coefficients of a quadratic equation A*X^2 + B*X + C = 0, your task is to determine the real roots of the equation. If no real ro...read more

Q42. LRU Cache Design Question

Design a data structure for a Least Recently Used (LRU) cache that supports the following operations:

1. get(key) - Return the value of the key if it exists in the cache; otherwise, re...read more

Q43. Diagonal Traversal of a Binary Tree

You are provided with a binary tree composed of integers. Your task is to determine all the diagonal paths within the binary tree. A diagonal path is defined as a sequence of...read more

Q44. Binary Search Tree Insertion

Given the root node of a binary search tree and a positive integer, you need to insert a new node with the given value into the BST so that the resulting tree maintains the properti...read more

Q45. Palindrome Partitioning Problem Statement

Given a string S, the task is to partition S so that every substring in the partition is a palindrome. Return all possible palindrome partitions of S.

Example:

Input:

S...read more

Q46. Number of Islands Problem Statement

You are provided with a 2-dimensional matrix having N rows and M columns, containing only 1s (land) and 0s (water). Your goal is to determine the number of islands in this ma...read more

Q47. Sort 0 1 2 Problem Statement

Given an integer array arr of size 'N' containing only 0s, 1s, and 2s, write an algorithm to sort the array.

Input:

The first line contains an integer 'T' representing the number of...read more

Q48. Possible Words From A Phone Number

After years of research, Ninja has invented a time machine and found himself in the era where T9 keypads were commonly used in mobile phones. Being curious, Ninja seeks to det...read more

Q49. Find K'th Character of Decrypted String

You are given an encrypted string where repeated substrings are represented by the substring followed by its count. Your task is to find the K'th character of the decrypt...read more

Q50. Ninja's Dance Competition Pairing Problem

Ninja is organizing a dance competition and wants to pair participants using a unique method. Each participant chooses a number upon entry, and Ninja selects a number ‘...read more

Q51. Reverse Stack with Recursion

Reverse a given stack of integers using recursion. You must accomplish this without utilizing extra space beyond the internal stack space used by recursion. Additionally, you must r...read more

Q52. Minimum Operation Needed to Convert to the Given String

You are given two strings str1 and str2. Determine the minimum number of operations required to transform str1 into str2.

Explanation:

An operation is def...read more

Q53. Flatten the Multi-Level Linked List

You are provided with a multi-level linked list containing N nodes. Each node has pointers next and child, which could potentially point to additional nodes. The task is to f...read more

Q54. 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 integer...read more

Q55. Boundary Traversal of a Binary Tree

Given a binary tree of integers, your task is to return the boundary nodes of the tree in Anti-Clockwise direction starting from the root node.

Input:

The first line contains...read more

Q56. Most Frequent Word Problem Statement

You are given two strings 'A' and 'B' composed of words separated by spaces. Your task is to determine the most frequent and lexicographically smallest word in string 'A' th...read more

Q57. Regular Expression Match Problem Statement

Given a string str and a string pat, where str may contain wildcard characters '?' and '*'.

If a character is '?', it can be replaced with any single character. If a c...read more

Q58. Infix to Postfix Conversion

Convert a given infix expression, represented as a string EXP, into its equivalent postfix expression.

Explanation:

An infix expression is formatted as a op b where the operator is p...read more

Q59. Division to N Decimal Places

Your task is to compute the division of two integers, X / Y, and output the result formatted to contain exactly N decimal places.

Input:

The first line contains an integer ‘T’, repr...read more

Q60. Design an elevator system for a single building with N floors.

Q61. Can you explain the basic theory behind mutexes and semaphores?

Q62. Design a search engine for a global retail application. Please include:

• Assumptions
• System considerations
• Design components

Q65. You are given a certain number of eggs and a building with a number of floors. The goal is to find the highest floor from which you can drop an egg without breaking it. What is the optimal strategy to minimize ...read more