Does the Type of Mining Algorithm (E.g. SHA-256 Vs Scrypt) Affect the Cost of a 51 Percent Attack?

Yes, the mining algorithm significantly affects the attack cost due to the availability of specialized hardware. Algorithms like SHA-256 (used by Bitcoin) have highly optimized ASIC miners, making the hashrate extremely concentrated and expensive to acquire.

Algorithms designed for general-purpose hardware (like GPUs or CPUs) have a more dispersed hashrate, which is often cheaper to rent in large quantities. The algorithm determines the efficiency of the available hardware, directly impacting the economic barrier to attack.