# 2034. Stock Price Fluctuation
###### tags: `Leetcode` `Medium`
Link: https://leetcode.com/problems/stock-price-fluctuation/
## 思路
注意update不是按照时间顺序给的，所以必须要记录下来所有之前的price
record map: key:timestamp, value:price
vals map: key: price, value: how many timestamp has $price$ as the current price
## Code

class StockPrice {
    Map<Integer, Integer> record;
    TreeMap<Integer, Integer> vals;
    int lastest = 0;
    public StockPrice() {
        record = new HashMap<>();
        vals = new TreeMap<>();
    }
    
    public void update(int timestamp, int price) {
        lastest = Math.max(lastest, timestamp);
        if(record.containsKey(timestamp)){
            int prevPrice = record.get(timestamp);
            vals.put(prevPrice, vals.get(prevPrice)-1);
            if(vals.get(prevPrice)==0) vals.remove(prevPrice);
        }
        record.put(timestamp, price);
        vals.put(price, vals.getOrDefault(price, 0)+1);
    }
    
    public int current() {
        return record.get(lastest);
    }
    
    public int maximum() {
        return vals.lastKey();
    }
    
    public int minimum() {
        return vals.firstKey();
    }
}