三明治数独中常见的错误有哪些？
最后更新
大多数错误的三明治盘面追溯到少数几个反复出现的错误——几乎都是概念性的而非算术性的。提前了解它们是可用的最便宜的难度升级。
数面包
The single most common error: including the 1 or the 9 in the clue sum. The clue counts only the digits strictly between them - The bread is never part of the filling. A related slip is building candidate combinations that include 1 or 9: a three-cell sandwich summing to 12 can never be {1,2,9}, because both of those digits already serve as the boundaries of the line's sandwich. Every combination you write down must come exclusively from {2,3,4,5,6,7,8}. If a deduction suddenly seems too easy, check whether you quietly let a 1 or 9 into the sandwich.
假设长度
线索12并不意味着两个单元格或三个——它意味着任何范围包含12的长度（两个单元格：5-15；三个单元格：9-21；甚至一个单元格被排除只是因为12 > 8）。在1和9实际定位之前，保持所有一致的长度开放，并使用长度范围来枚举它们。过早承诺一个长度的解题者往往会在二十个放置后发现矛盾，此时撤销代价高昂。线索约束几何形状；它不决定它。
浪费自由信息
Two omissions cost the most time. First, deprioritising the extreme clues: 0 and 35 (and near-extremes like 2-4 and 33) should always be processed before anything else, because they fix geometry instantly. Second, forgetting the outside of the sandwich: the digits outside always sum to 35 − clue, and with large clues that outside total is tiny and brutally constraining. Re-scan both sides of every clue line after each placement - The line you solved half of often finishes itself.