HCL Tech | Backend Engineer

Problem: sharing account

Given a list of customer ids and accounts ids we'd like to know how many groups of customers share all the same accounts

For this example:
Customers 1 and 3 share all of their accounts, 10 and 11, so they are a match.
Customers 2 and 4 share account 13 but customer 4 also owns account 14, which customer 2 doesn't. They are not a match.

My solution

def sharedAccounts (customerAccounts)
    res = Set.new
m.keys.each do |customer1|
    accounts1 = m[customer1]
    tmp_res = []

    m.keys.each do |customer2|
        next if customer1 == customer2
        
        accounts2 = m[customer2]
        
        if accounts1 == accounts2
            tmp_res << customer2
        end
    end

    if !tmp_res.empty?
        res.add((tmp_res + [customer1]).sort)
    end
end

# Time complexity: O(n^2)

res.to_a

end