棋盘填数问题 在N*N的棋盘上（1<=N<=10）请填入1，2，...N2共N2个数，使得任意两个相邻的数之和为素数。 填写的方案如： 在这里我们约定：左上角的格子里必须放数字1。 输出：如有多种解，则输出第一行，第一列之和为最小的排列方案；若无解，则输出“NO Answer”-chessboard fill in N* N on the chessboard (1LT; = Nlt; = 10) Please insert 1,2, ... N2 N2 total number, making any two adjacent few and as a prime number. Fill in the program, such as : Here, we agreed : the upper left corner of the grid must be put in the yard a figure. Output : For a variety of solutions, the first line of output, the first out and as a program with the smallest; If not solved, then the output "NO Answer"