2034. Stock Price Fluctuation

class StockPrice {
   
    private Map<Integer, Integer> timestampPriceMap;
    private TreeMap<Integer, Integer> priceFrequency; // sorted map
    private int latestTime;
    
    public StockPrice() {
        timestampPriceMap = new HashMap<>();
        priceFrequency = new TreeMap<>();
        latestTime = 0;
    }
    
    public void update(int timestamp, int price) {
        if (timestampPriceMap.containsKey(timestamp)) {
            int oldPrice = timestampPriceMap.get(timestamp);
            priceFrequency.put(oldPrice, priceFrequency.get(oldPrice) - 1);
            if (priceFrequency.get(oldPrice) == 0) {
                priceFrequency.remove(oldPrice);
            }
        }
        timestampPriceMap.put(timestamp, price);
        priceFrequency.put(price, priceFrequency.getOrDefault(price, 0) + 1);
        
        if (timestamp > latestTime) {
            latestTime = timestamp;
        }
    }
    
    public int current() {
        return timestampPriceMap.get(latestTime);
    }
    
    public int maximum() {
        return priceFrequency.lastKey();
    }
    
    public int minimum() {
        return priceFrequency.firstKey();
    }
}

/**
 * Your StockPrice object will be instantiated and called as such:
 * StockPrice obj = new StockPrice();
 * obj.update(timestamp,price);
 * int param_2 = obj.current();
 * int param_3 = obj.maximum();
 * int param_4 = obj.minimum();
 */