Microsoft Software Engineer Intern interview questions

got the interview opportunity from on campus interview, questions how to rotate the matrix , how to find different ways to solve a linear equation, and implementation, on site interview, 1. link list question, delete and add link nodes 2. use "object" concept to design linkedin 3. how to optimize the memory in finding the frequency of some number in the given long array 4. how to use bst to find the exact number

HR emailed the description based on my resume. Scheduled an interview on campus.