Microsoft Intern - Software Engineer interview questions

It was a campus event through the career fair. Was asked to implement breadth first B-tree parsing algorithm and to write a code. I was then given a string with unknown length in which I had to sort the alphabets from the numerals in-string.(no other variable allowed.)

It was on Campus Interview for intern selection , the first round was a written test consisting of five questions ,all related to coding , the second , third and fourth round was a 1:1 interview in which each inter viewer asked me to write one code for the questions . The last was that taken by a Senior General Manager at his hotel suite who gave us two write two codes to write , one at a time.