线索35是什么意思？

The digits available to fill a sandwich are 2, 3, 4, 5, 6, 7, and 8 - The 1 and 9 are the boundaries and digits cannot repeat in a line. Those seven digits sum to 2+3+4+5+6+7+8 = 35. A clue of 35 therefore requires every one of them to be inside the sandwich: seven sandwiched cells plus the two bread cells accounts for all nine cells in the line. The only way to fit that is with the 1 and 9 in the first and last cells. No other clue value forces the full span, and 34 is impossible altogether - Dropping any digit from the full set loses at least 2.

立即用candidate pair {1,9}标记行的两个端点单元格，并从七个内部单元格中移除1和9作为candidates。这就是一个naked pair在行的端点上：任何包含这些端点单元格之一的其他line或box都不能再自由地放置自己的1或9。决定哪个端点持有1，哪个持有9通常来自crossing clues - 通过一个端点单元格的column可能无法在该位置容纳9，从而同时确定两个端点。

线索33值得同样的尊重。六个夹心单元格总和为33意味着恰好有一个来自2-8的数字在夹心之外，它必须是35 − 33 = 2。所以1和9相隔七个单元格——位置(1,8)或(2,9)——而单个剩余单元格持有数字2。同样的逻辑给出线索27的剩余数字为8。高线索几乎像35本身一样压缩行的几何形状。