数独只有一条规则：在图中格子内填入1到9的数字使每行、列、3×3的宫（我们把行，列和宫统一称做：规则）内数字不重复，数字可以是任何顺序，不限制斜线上数是否重复

宫：就是将9*9的区域划分成9个3*3的区域，且每个区域中1-9只能出现一次-Fill in the game board so that the numbers 1 through 9 occur exactly once in each row, column, and 3x3 box(we call it RULE). The numbers can appear in any order and diagonals are not considered.