OPPO Interview Questions and Answers

Strings are immutable in Java to ensure thread safety and prevent unintended changes.

• Immutable objects are safer to use in multi-threaded environments

• String pool optimization is possible because of immutability

• StringBuffer and StringBuilder classes are available for mutable string operations

Finding common elements in two sorted linked lists.

• Traverse both lists simultaneously using two pointers.

• Compare the values of the nodes pointed by the two pointers.

• If they are equal, add the value to the result list and move both pointers.

• If not, move the pointer pointing to the smaller value.

• Repeat until one of the lists is fully traversed.

Finding the Kth element after merging two sorted arrays.

• Merge the two sorted arrays into a single array.

• Sort the merged array.

• Return the Kth element from the merged and sorted array.

String pool is a cache of string literals stored in memory for efficient reuse.

• String pool is a part of Java's memory management system.

• It stores a collection of unique string literals to save memory.

• When a new string is created, it is first checked in the pool and reused if already present.

• String pool can be accessed using the intern() method.

• Example: String s1 = "Hello"; String s2 = "Hello"; s1 and s2 will point to the same object in the pool.

Graph implementation involves creating nodes and edges to represent data and relationships.

• Nodes represent data points and edges represent relationships between them

• Graphs can be directed or undirected

• Common graph algorithms include BFS, DFS, and Dijkstra's algorithm

To find the diameter of a binary tree, we need to find the longest path between any two nodes in the tree.

• Traverse the tree recursively and calculate the height of the left and right subtrees.

• Calculate the diameter of the left and right subtrees recursively.

• The diameter of the tree is the maximum of the following three values: 1. Diameter of the left subtree 2. Diameter of the right subtree 3. Height of the left subtree + height of the right subtree + 1

• Example: 1 / \ 2 3 / \ ...read more