He asked very different questions than my profile and skills. The first question was on Huffman coding, and he asked if I remembered it, implying I must have studied it in college. Who remembers after 13-14 years?

I do not know why interviewers interview people when they are sitting for rejection.

Very bad experience.

First question was about Huffman coding. Write a code for the same.

Asked about image processing, define a 2D array as a struct of structs. Allocate memory to a 2D array dynamically (int **arr).

What is a Hash map? Write a struct for that.

What is a histogram and how are values mapped? Calculate the frequency of numbers in a 2D matrix, like in image processing, the pixel frequency in a 2D array.