Given a list of numbers, this Python program finds the first unique element in the list. For example, given the input [1, 2, 3, 4, 5, 1, 2 , 3, 4], the output would be 5.
About this solution: The candidate's solution is correct and demonstrates a level of completeness. The candidate's approach is also correct, as it uses a dictionary to store the number of times each element appears in the list. This approach is optimal because it only iterates through the list once and then iterates through the dictionary once. Therefore, the time complexity is O(n) where n is the size of the list.
This technical problem asks the reader to write a SQL query to find the top 10 customers by total spend. The table of customer data is provided as an example, and the expected output is also provided.
About this solution: The candidate's solution is correct and demonstrates a good understanding of SQL. The solution is optimal, using the ORDER BY and LIMIT clauses to sort the table by total_spend in descending order and then limit the results to the top 10 customers.