The permutation is even if the numberof inversions it contains is even.
如果一个排列中含有的反序的个数是偶数,则称它为偶排列。
2
The permutation law and decision method of prime number is an important question of the number theory.
素数的排列规律和鉴别方法一直是数论中研究的重要问题之一。
3
Because each permutation is generated for each possible numberof arguments, the included file size grows exponentially in terms of the number of constructor arguments, not linearly.