求教一道DS题目

A certain list contains of several different integers. Is the product of all the integers in the list positive?

1. The product of the greatest and smallest of the integers in the list is positive

2. There is an even number of integers in the list

请教NN帮忙题意及解题思路~

呃，有思路的同志讲解一下吧，一道prep上的题，没有头绪...@@