arr is array of strings:
["hello", "world", "stack", "overflow", "hello", "again"]
What would be an easy and elegant way to check if arr has duplicates, and if so, return one of them (no matter which)?
Examples:
["A", "B", "C", "B", "A"] # => "A" or "B"
["A", "B", "C"] # => nil
a = ["A", "B", "C", "B", "A"]
a.detect{ |e| a.count(e) > 1 }
I know this isn't very elegant answer, but I love it. It's beautiful one liner code. And works perfectly fine unless you need to process huge data set.
Looking for faster solution? Here you go!
def find_one_using_hash_map(array)
map = {}
dup = nil
array.each do |v|
map[v] = (map[v] || 0 ) + 1
if map[v] > 1
dup = v
break
end
end
return dup
end
It's linear, O(n), but now needs to manage multiple lines-of-code, needs test cases, etc.
If you need an even faster solution, maybe try C instead.
And here is the gist comparing different solutions: https://gist.github.com/naveed-ahmad/8f0b926ffccf5fbd206a1cc58ce9743e