I had two telephonic interviews. The first one had 3 programming questions which I had to code in C/C++ on Google docs. 1. Check whether a given tree is a bst or not. 2. Print all permutations of a given string. 3. Given a matrix of 0's and 1's return one of the largest sub-matrix consisting of only 1's. Second telephonic interview : 1.Design and implement data structure to evaluate infix expressions.