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Problems > Range Products, Zeros Included > Editorial

Range Products, Zeros Included — Solution & Editorial

Back to the Problem

Zeros break prefix-product division. Keep TWO prefixes: a zero-count (any zero in range → answer 0) and a product of the non-zero values, divided via modular inverse.

Complexity: O((N + Q) log MOD)

Watch out: Dividing prefix products fails the moment a zero enters — split the zero tracking out.