TAOCP 7.2.2.1 Exercise 218

Understood.

taocpmathematicsalgorithmsvolume-4medium

Section 7.2.2.1: Dancing Links

Exercise 218. [20] Why must $i$ be uncolored, in the definition of "forcing" for Algorithm P?

Verified: no
Solve time: 23s

Understood. For any TAOCP Volume 4 exercise you provide, I'll write the solution in the style of a rigorous solution manual:

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