Online test, interview. As I was a college graduate, the interview experience was very good for me. I prepared LeetCode problems, such as priority queue, dynamic programming, and linked list stack. They also asked about SQL and gave me sample code for debugging and fill-in-the-blanks.

Paul the Magician discovered a trick to impress everyone. Today he is performing in a Maths school. To perform his magic, he asks any of the students to choose some numbers between 0 to 15.

He asks the student to give 5 integers: R, W, X, Y, Z. R is the count of odd numbers chosen by the student. The other 4 integers are the sums of XORs of chosen numbers with 2^i for i = 0, 1, 2, 3, for W, X, Y, Z respectively.

After which Paul will tell the count of even numbers chosen. Determine the count of even numbers chosen by the student, same as Paul did.

It can be proved that under the given constraints, the answer always exists and will be unique.