都是地里的题目，一题是maximal common，另外一体是strange sort数学考得比较简单，都是概率，微积分，除了一题考虑transition matrix。
祝大家找工作顺顺利利！
HackerRank Test
Given a matrix of integers, the task is to find out the number of positional elements. A positional element is one which is either minim
maximum in a row or in a column. If there are multiple minimum or maximum elements in a row or a column, return -1.
0/1 Knapsack problem. One more addition is that you had to tell which all items were chosen for the optimal solution.