之间线Between Lines

标准数独基础上，圆圈之间线条上的数字，大小范围在圆圈两个数之间。

Classic rules applied. Additionally, numbers on lines between two circle, cannot be larger or smaller than numbers on circle.

显然，在N阶题目中，1和N不能在线条上。以及，如果线条上有M个不同数字，两个圆圈的差值至少要有M+1。

It is obviously that in NxN puzzles, 1 and N cannot on any lines. And if there're M different cells on line, the difference of the two circles should be at least M+1.

练习 Practice

① 解答问号格 Find out the ？cells.

答案 Answer

① A7=6; D1=3.