Stock Analysis

In data analysis, the eliminate algorithm determines the single final value to use for each data parameter. The eliminate algorithm works in the following way:

• Data is acquired from multiple sources in order from least to most preferred, i.e if a parameter P is present in both source 1 and source 2, the parameter from the higher priority source, source 2, is used in the final parameter list, and any value from an earlier source is superseded.
• As new parameters arrive, they are added to the list.
• If a parameter P is present only in one of the sources, it is directly added to the final parameter list.

Hence,

• The result of performing the above operations until all parameters from source 1 and source 2 are exhausted is the result of Eliminate-algorithm(source 1, source 2).
• Each time a new value for a parameter is encountered from a higher preferred site, the old data is superseded.
• Assuming three sources S₁, S₂, S₃:
  • Eliminate-algorithm(S₁, S₂, S₃) = Eliminate-algorithm (Eliminate-algorithm(S₁, S₂), S₃).

Given a list of sources S₁, S₂...Sₙ, find the final parameter list given by Eliminate-algorithm(S₁, S₂...Sₙ). Maintain your results in the order a key was first encountered.

For example, a rating parameter of buy, sell or hold from three sources in increasing order of preference: [buy, sell, hold], where buy is from S₁, immediately superseded by sell S₂, immediately superseded by hold S₃. The final rating is the only one that hasn't been superseded, so you use 'hold' as the final rating.