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40 changes: 32 additions & 8 deletions lib/practice_exercises.rb
Original file line number Diff line number Diff line change
@@ -1,13 +1,37 @@

# Time Complexity: ?
# Space Complexity: ?
require 'pry'
# Time Complexity: O(n)
# Space Complexity: O(n)
def remove_duplicates(list)
raise NotImplementedError, "Not implemented yet"
len = list.length
if len == 1 || len == 0
return list
end

new_list = []
(0..len-1).each do |i|
if list[i] != i
new_list << list[i]
end
Comment on lines +12 to +14

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This is only not adding elements if they are not equal to their index, which won't work in all cases.

Consider:

   it "will remove duplicates for even longer arrays " do
      expect(remove_duplicates([1, 1, 1, 1, 1, 2, 2, 3, 3, 4, 4, 4, 4, 4])).must_equal [1, 2, 3, 4]
    end

end
return new_list
end

# Time Complexity: ?
# Space Complexity: ?
# Time Complexity: O(n^2)

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This is actually O(nm) where m is the length of the shortest word.

# Space Complexity: O(n)

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Given the above space complexity is O(m)

def longest_prefix(strings)
raise NotImplementedError, "Not implemented yet"
end

result = ""
i = 0

strings[0].each_char do |letter|
strings.each do |string|
if letter != string[i]
return result
end
end

result += letter
i += 1
end
return result
end
1 change: 1 addition & 0 deletions test/practice_exercises_test.rb
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@

it "will remove duplicates for longer arrays" do
expect(remove_duplicates([1, 2, 2, 3, 3, 4])).must_equal [1, 2, 3, 4]
# expect(remove_duplicates([1, 2, 2, 3, 3, 4, 5, 5])).must_equal [1, 2, 3, 4, 5]
end
end

Expand Down