Stripe 電面分享

Stripe Tech Phone interview.

1. # For this interview, imagine that we are working with a simple database. Each row
   
2. # associates column names (strings) with integer values (for example: 5, 0, -3,
   
3. # and so on). Here's a table with three rows:
   
4. 
   
5. # a b c d
   
6. # ---------------
   
7. # 1 0 0 0
   
8. # 0 2 3 0
   
9. # 0 0 0 4
   
10. 
    
11. # We can choose to represent a database table in JSON as an array of objects. For
    
12. # example, the previous table could be written as:
    
13. 
    
14. # [ {"a": 1, "b": 0, "c": 0, "d": 0},
    
15. # {"a": 0, "b": 2, "c": 3, "d": 0},
    
16. # {"a": 0, "b": 0, "c": 0, "d": 4} ]
    
17. 
    
18. # (There is no need to use JSON in your solutions -- the notation is just used to
    
19. # introduce and explain the problems.)
    
20. 
    
21. # Write a function minByColumn that takes a database table (as above), along with a
    
22. # column, and returns the row that contains the minimum value for the given column.
    
23. # If a row doesn't have any value for the column, it should behave as though the
    
24. # value for that column was zero.
    
25. 
    
26. # In addition to writing this function, you should use tests to demonstrate that it's
    
27. # correct, either via an existing testing system or one you create.
    
28. ## Examples
    
29. 
    
30. # table1 = [
    
31. # {"a": 1},
    
32. # {"a": 2},
    
33. # {"a": 3}
    
34. # ]
    
35. # minByColumn(table1, "a") returns {"a": 1}
    
36. 
    
37. # In part 1 you may have noticed that it's possible for two rows to be "tied",
    
38. # meaning that either would be an acceptable return value from minByColumn.
    
39. # Consider:
    
40. 
    
41. # table4 = [
    
42. # {"a": 1, "b": 2},
    
43. # {"a": 1, "b": 3},
    
44. # {"a": 1, "b": 4}
    
45. # ]
    
46. # minByColumn(table4, "a") returns ???
    
47. 
    
48. # Since all three rows have the same value for a, all three rows are acceptable
    
49. # candidates to be returned by minByColumn(table, "a").
    
50. 
    
51. # In these cases it would be nice if users could specify additional columns (e.g. "b")
    
52. # to use as tie-breakers. A tie-breaker would only apply in cases where multiple rows
    
53. # share the same minimum value. In `table4` above, the row {"a": 1, "b": 2} is
    
54. # tied for the smallest "a" value (1) and of all the tied candidates, it has the
    
55. # smallest "b" value (2). If two records had equal values for "a" and also for "b" then
    
56. # another tie-breaker (e.g. "c") could be used. When records are tied with respect to
    
57. # all columns, either record may be considered the minimum.
    
58. 
    
59. # Write a function minByOrder that takes a database table and a list of columns, and
    
60. # returns the row with the minimum column values using the tie-breaking logic above.
    
61. # If only one column is provided, then the behavior of minByOrder is identical to
    
62. # passing that column to minByColumn:
    
63. 
    
64. # minByOrder(table, [column]) is equal to minByColumn(table, column)
    
65. 
    
66. # As in Part 1, you should use tests to demonstrate that it's correct, either via an
    
67. # existing testing system or one you create.
    
68. 
    
69. # ## Examples
    
70. # table5 = [
    
71. #   {"x": 1, "y": 3},
    
72. #   {"x": 1, "y": 0}
    
73. # ]

复制代码

面試時傻了，沒仔細想清楚這題目的真正問題。直接硬上寫了很多方程式來解決問題。

您好！
本帖隐藏的内容需要积分高于 188 才可浏览
您当前积分为 0。
使用VIP即刻解锁阅读权限或查看其他获取积分的方式

游客，您好！
本帖隐藏的内容需要积分高于 188 才可浏览
您当前积分为 0。
VIP即刻解锁阅读权限 或 查看其他获取积分的方式
Unlock interview details and practice with AI
Curated Interview Questions from Top Companies

面分享我的解法

1. import sys
   
2. 
   
3. def getValue(item, key):
   
4.   # since we find the smallest one,
   
5.   # default to sys max int if there is no key is provided in the item (column).
   
6.   return item.get(key, sys.maxint)
   
7. 
   
8. def minByColumn(table, column):
   
9.   return sorted(table, key=lambda i: getValue(i, column))[0]
   
10. 
    
11. def minByOrder(table, columns):
    
12.   return sorted(table, key=lambda i: tuple([getValue(i, c) for c in columns]))[0]
    
13. 
    

复制代码

歡迎大家不吝嗇指教

lz过了么

请问楼主面的是哪个职位呀？

楼主过了么

这题地里之前没有哎

求问楼主OA后多久的电面呀

minByColumn 只需要o(n) 扫一遍，看min就好了，不需要sort o(nlogn)把