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9461f74 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | defmodule Bob.Hasher do
@moduledoc """
Bob's implementation of the integer hashing challenge.
Uses iterative approaches for better performance.
"""
@doc """
Computes SHA-256 hash of a string.
"""
def sha256(input) do
:crypto.hash(:sha256, input) |> Base.encode16(case: :lower)
end
@doc """
Sums a list of integers iteratively.
"""
def sum_list(list) do
do_sum(list, 0)
end
defp do_sum([], acc), do: acc
defp do_sum([head | tail], acc), do: do_sum(tail, acc + head)
@doc """
Computes factorial iteratively.
"""
def factorial(n) do
do_factorial(n, 1)
end
defp do_factorial(0, acc), do: acc
defp do_factorial(n, acc), do: do_factorial(n - 1, acc * n)
@doc """
Main entry point that routes to the appropriate function.
"""
def solve(:sha256_forge, input), do: sha256(input)
def solve(:sum_list, input), do: sum_list(input)
def solve(:factorial_5, input), do: factorial(input)
def solve(_challenge, _input), do: nil
end
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