AlphaSense Data Engineer Interview Questions and Answers

Find an odd occurring number among even occurring numbers.

• Use XOR operation to cancel out even occurring numbers and get the odd occurring number.

• Iterate through the array and XOR each element with the result variable.

• The final result will be the odd occurring number.

Print the spiral order of a binary tree and matrix.

• For binary tree, use level order traversal and alternate direction for each level.

• For matrix, use four pointers to traverse in spiral order.

• Example for binary tree: 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9

• Example for matrix: 1 2 3 4 -> 8 7 6 5 -> 9 10 11 12 -> 16 15 14 13

Finding pairs in an array with a given sum.

• Iterate through the array and for each element, check if the difference between the given sum and the element exists in the array.

• Use a hash table to store the elements of the array and their indices for faster lookup.

• If there are multiple pairs with the same sum, return any one of them.

• If no pair is found, return null or an empty array.

Find total number of k element with given avg in an array in minimum time complexity.

• Use sliding window technique to traverse the array in O(n) time complexity.

• Maintain a sum variable to keep track of the sum of elements in the window.

• If the sum of elements in the window is equal to k times the given avg, increment the count.

• Move the window by subtracting the first element and adding the next element in the array.

Printing non-boundary elements of a binary tree

• Traverse the tree in any order (preorder, inorder, postorder)

• Check if the current node is not a boundary node (not the first or last node in its level)

• If it is not a boundary node, print its value

• Recursively traverse its left and right subtrees

Check if left child is less than right child in a binary tree

• Traverse the tree recursively and compare left and right child values

• Use a stack to traverse the tree iteratively and compare left and right child values

• Return true if all left children are less than right children, else false

Use built-in string method to check substring presence for faster execution.

• Use 'indexOf' method to check if substring is present in the main string.

• If the method returns -1, the substring is not present.

• If the method returns a non-negative integer, the substring is present.

App performance analysis involves identifying and resolving bottlenecks to improve user experience.

• Collect and analyze performance metrics such as response time, CPU usage, memory usage, and network latency.

• Identify and prioritize bottlenecks based on impact on user experience and frequency of occurrence.

• Implement optimizations such as caching, code refactoring, and database tuning.

• Continuously monitor and test perform...read more

To find a loop in a directed graph, use Floyd's cycle-finding algorithm. To find the last element in a binary tree, traverse the tree and return the rightmost leaf node.

• For finding a loop in a directed graph, use Floyd's cycle-finding algorithm which uses two pointers moving at different speeds.

• To find the last element in a binary tree, traverse the tree recursively or iteratively and return the rightmost leaf node.

The question is about finding the last number in a circular queue that has the highest number of digits.

• Implement a circular queue data structure

• Iterate through the circular queue to find the last number with the highest number of digits

• Compare the number of digits of each number in the circular queue

• Keep track of the last number with the highest number of digits

Print all downward paths from any node in a binary tree with sum of elements equal to N.

• Traverse the binary tree and keep track of the sum of elements in the path from root to current node.

• If the sum equals N, print the path from root to current node.

• Recursively traverse the left and right subtrees with updated sum.

• Use a stack to keep track of the current path being traversed.

• Example: Binary tree with root 1, left chil...read more

Yes, it is possible to get the accurate result from the given data.

• The coordinates (i,j,k) where metallic balls are present can be determined by finding the set elements in both matrix1 and matrix2.

• Additional data is not required as the given data is sufficient to determine the coordinates.

• The coordinates can be obtained by iterating through the elements of matrix1 and matrix2 and checking for set elements.