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March 7, 2017 16:02
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PhillyDev Slack #daily_programmer for March 7, 2017
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defmodule HammingDistance do | |
@moduledoc """ | |
Write a program that can calculate the Hamming distance between two DNA | |
strands. | |
A mutation is simply a mistake that occurs during the creation or copying of a | |
nucleic acid, in particular DNA. Because nucleic acids are vital to cellular | |
functions, mutations tend to cause a ripple effect throughout the cell. | |
Although mutations are technically mistakes, a very rare mutation may equip | |
the cell with a beneficial attribute. In fact, the macro effects of | |
evolution are attributable by the accumulated result of beneficial | |
microscopic mutations over many generations. | |
The simplest and most common type of nucleic acid mutation is a point | |
mutation, which replaces one base with another at a single nucleotide. | |
By counting the number of differences between two homologous DNA strands taken | |
from different genomes with a common ancestor, we get a measure of the | |
minimum number of point mutations that could have occurred on the | |
evolutionary path between the two strands. | |
This is called the “Hamming Distance”. | |
GAGCCTACTAACGGGAT | |
CATCGTAATGACGGCCT | |
^ ^ ^ ^ ^ ^^ | |
The Hamming distance between these two DNA strands is 7. | |
""" | |
@doc """ | |
Given two strings - returns the hamming distance | |
# Example | |
iex> HammingDistance.hammit("GAGCCTACTAACGGGAT", "CATCGTAATGACGGCCT") | |
7 | |
iex> HammingDistance.hammit("GAGCCTACTAACGGGAT", "GAGCCTACTAACGGGAT") | |
0 | |
""" | |
@spec hammit(String.t, String.t) :: non_neg_integer | |
def hammit(left, right) do | |
left | |
|> String.graphemes | |
|> Enum.zip(right |> String.graphemes) | |
|> Enum.filter(fn({left, right}) -> left != right end) | |
|> Enum.count | |
end | |
end |
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