Oracle Cerner Senior Technical Staff Member 1 Interview Questions, Process, and Tips

HashMap is a data structure that stores key-value pairs and uses hashing to efficiently retrieve values based on keys.

• HashMap internally uses an array of linked lists to store key-value pairs.

• When a key-value pair is added, the key is hashed to determine the index in the array where it will be stored.

• If multiple keys hash to the same index, a linked list is used to handle collisions.

• To retrieve a value, the key is hash...read more

Find anagrams from a string array

• Iterate through each string in the array

• Sort the characters of each string to create a key for comparison

• Use a hashmap to group anagrams together

• Return the grouped anagrams as arrays

A top view of a binary tree shows the nodes visible when looking at the tree from the top.

• The top view of a binary tree is the set of nodes visible when looking at the tree from the top.

• Nodes at the same horizontal distance from the root are considered at the same level.

• Use a map to store the horizontal distance of each node and only keep the first node encountered at each horizontal distance.

Height of a binary tree is the maximum number of edges on the longest path from the root node to a leaf node.

• Height of an empty tree is -1

• Height of a tree with only one node is 0

• Height of a binary tree can be calculated recursively by finding the height of left and right subtrees and adding 1 to the maximum of the two heights