stocks.py

'''
You are given a snapshot of a queue of stocks that have changing prices coming in from a stream. Remove the outdated stocks from the queue.

Example:
$ snapshot = [
  { sym: ‘GME’, cost: 280 },
  { sym: ‘PYPL’, cost: 234 },
  { sym: ‘AMZN’, cost: 3206 },
  { sym: ‘AMZN’, cost: 3213 },
  { sym: ‘GME’, cost: 325 }
]
$ stockQueue(snapshot)
$ [{ sym: ‘PYPL’, cost: 234 },
   { sym: ‘AMZN’, cost: 3213 },
   { sym: ‘GME’, cost: 325 }]

'''
from collections import defaultdict
def RemoveOutdatedStocks(snapshot):
  stocks = defaultdict(int)

  for stock in snapshot:
    sym, cost = stock['sym'], stock['cost']
    stocks[sym] = cost
  
  mostRecent = []
  for sym, cost in stocks.items():
    mostRecent.append({'sym': sym, 'cost': cost})

  return mostRecent

stocks = [
  { 'sym': 'GME', 'cost': 280 },
  { 'sym': 'PYPL','cost': 234 },
  { 'sym': 'AMZN','cost': 3206 },
  { 'sym': 'AMZN','cost': 3213 },
  { 'sym': 'GME', 'cost': 325 }
]
print(RemoveOutdatedStocks(stocks))