Bloomberg面经Senior职位

夏绿蒂

I think they wanted to see how you would design this with your own classes. Using your own classes also means you can easily keep track of the highest value / lowest value in a listing as you consume the stream, getRatio() can then be O(1).

e.g.

public class StockCompany {

/ J, Y) |- F, a6 M' H: ~! l. e    private final String name;

, m+ M$ H' ?2 z; d; K4 F    public StockCompany(String name) {
        this.name = name;
    }

    public String getName() {
( H' [0 x( v* ~2 S1 [4 H0 d        return name;
    }
}

public class StockListing {

    private final StockCompany company;
# H' c: U! d5 K' P* V" Y    private final List<StockValue> values;

    private StockValue highestStockValue;
    private StockValue lowestStockValue;

    public StockListing(StockCompany company, StockValue initialStockValue) {
) E8 ^# a3 @/ U2 e1 h3 s$ H        this.company = company;
        this.values = new ArrayList();
# I' [3 |5 W9 B; q: y0 f+ L8 u        if(initialStockValue == null) {
            throw new StockListingInitialValueNullException();
        }
3 t0 s- P- z6 i& r1 [0 ~6 b: C        this.values.add(initialStockValue);
& y! p' ~* j& F2 E$ [. f        highestStockValue = initialStockValue;
6 J0 Y3 h. }2 l        lowestStockValue = initialStockValue;
% A- I" y, i' Y, ^& ?    }

0 v% Q6 J) d  h  P' a# [    public StockCompany getCompany() {
/ U9 {) d( z& M        return company;
    }

    public List<StockValue> getValues() {
4 f* W+ `+ R( u$ f        return Collections.unmodifiableList(values);
# q  l: n% F) U! b& X" X9 l    }

    public void addValue(StockValue stockValue) {
        this.values.add(stockValue);
        if(stockValue.getValue() > highestStockValue.getValue()) {
            highestStockValue = stockValue;
7 L7 m& T9 j& `. |' M+ t3 b1 I# @        } else if(stockValue.getValue() < lowestStockValue.getValue()) {
7 \, n; s8 m: A7 J. ]- P            lowestStockValue = stockValue;
        }
    }

2 z; Q. X- y  j. W- ]    public float getLowestToHighestRatio() {
        return lowestStockValue.getValue() / highestStockValue.getValue();
    }
) J  e; h4 O# i+ ]}

public class StockValue {
* o1 ~0 V$ n' r& K7 V4 \
    private final float value;
2 S7 d5 u4 A( e& |- K
    public StockValue(float value) {
        this.value = value;
, S7 m8 ]. P3 ^* ]    }
' v4 A& _& L! h2 _3 q; Y7 [
    public float getValue() {
        return value;
    }
; C8 p) P! ]5 f9 ~8 k( W  F; `}

public class StockListingInitialValueNullException extends RuntimeException {
" N1 r' c# s* s7 A& i. V1 y$ ]
2 B$ |: @/ ~$ {" ~/ z4 s" F2 }5 C    public StockListingInitialValueNullException() {
/ ?* \% r+ `9 M0 l2 {        super("Stock listing can not have a null initial stock value");
    }
- M6 w6 O, ^6 h
}

7878wo

感谢Powerful发帖~~~

Cecil_Cai

好帖~~~学习了~~~