ServiceNow Software Development Engineer interview questions

Variation of the problem : Find the first occurred 1 in a sorted 2D matrix which contains only 0's and 1's

1) Spiral printing of a binary tree 2) Number of ways to reach Nth step if you are permitted to take 1, 2 and 3 steps 3) Given a string find the length of the longest substring having consecutive characters. Eg: abcwxyz, here the ans is 4 because of the substring wxyz. 4) Find diameter of a tree. (it may be any tree... not restricted to binary tree) 5) Given N points, find the most number of points which are on a straight line. i.e they are collinear. (these points are not necessarily axis aligned, they may be diagonal as well).