Josh Technology Group Front end Developer Interview Questions and Answers

The solution checks if an integer array can become non-decreasing by modifying at most one element.

• Iterate through the array and check if there are more than one decreasing pairs of elements.

• If there are more than one decreasing pairs, return false.

• If there is only one decreasing pair, check if modifying one of the elements can make the array non-decreasing.

• If modifying the element at index i-1 or i can make the array non-decreasing, return true.

• Otherwise, return false.

The task is to find the unique number in an array where all other numbers occur twice.

• The array size is given by N = 2M + 1, where M is the number of elements occurring twice.

• Loop through the array and use a hashmap to count the occurrences of each number.

• Return the number with a count of 1, as it is the unique number.

The task is to sort a singly linked list based on actual values instead of absolute values.

• Traverse the linked list and store the values in an array

• Sort the array using any sorting algorithm

• Create a new linked list using the sorted array

• Return the new linked list

Check if a given singly linked list of integers is a palindrome or not.

• Create a function to reverse the linked list.

• Use two pointers to find the middle of the linked list.

• Compare the first half of the linked list with the reversed second half to determine if it's a palindrome.

The diameter of a binary tree is the length of the longest path between any two end nodes in the tree.

• The diameter of a binary tree can be calculated by finding the maximum of the following three values: 1) the diameter of the left subtree, 2) the diameter of the right subtree, and 3) the longest path that passes through the root node.

• To find the diameter of a binary tree, we can use a recursive approach. We calculate the height of the left and right subtrees, and then calcul...read more

Merge K sorted arrays into a single sorted array.

• Create a min heap to store the first element of each array along with the array index.

• Pop the top element from the heap, add it to the result array, and push the next element from the same array back to the heap.

• Repeat the process until all elements are processed.

• Time complexity: O(N log K) where N is the total number of elements and K is the number of arrays.

Rearrange a linked list such that odd numbers appear before even numbers while preserving the order.

• Create two separate linked lists for odd and even numbers

• Traverse the original list and append nodes to respective odd/even lists

• Combine the odd and even lists while maintaining the order

• Return the rearranged linked list