笼区内数字可以重复吗？

Killer Sudoku cages always sit within rows, columns, and boxes. When cage cells share the same row, column, or box the standard Sudoku no-repeat rule already prevents repetition. But even when cage cells span multiple rows, columns, and boxes, the cage itself carries an independent no-repeat constraint.

This is an inherent rule of Killer Sudoku - It is always in effect on every cage, regardless of size or position.

Without the no-repeat rule, a 3-cell cage summing to 9 could include dozens of digit combinations including {3,3,3}. With the rule, only {1,2,6}, {1,3,5}, and {2,3,4} are valid - Three combinations instead of many more. This restriction is exactly what makes forced combinations possible: a 2-cell cage of 3 must be {1,2} because no other unique pair of digits 1-9 sums to 3.

每次你确认一个笼单元格中的数字，该数字作为候选数从同一笼中的所有其他单元格中消除——即使它们位于不同的行、列和宫中，否则该数字会被标准数独规则允许。这是杀手数独独有的额外消除来源。