Currency Exchange

Currency Exchange Given a set of exchange rates, find the best exchange rate between two currencies. The rates can be represented as a directed graph where nodes represent currencies and edges represent exchange rates. Given three inputs: starting currency code, target currency code, and all currency exchange paths, output the optimal exchange rate. Input: Four lines of input, each in separate lines. Starting currency code (string) Target currency code (string) Total currency count (n) List of all exchange rates, each element is a string representing exchange rate information between two currencies Output: Optimal exchange rate (float) Example: USD EUR 3 USD->JPY,100.0 JPY->EUR,0.01 USD->EUR,1.5 Output: 1.5 Constraints: Exchange rates may contain up to 1 million records. Example Input USD EUR 3 USD->JPY,100.0 JPY->EUR,0.01 USD->EUR,1.5