1331. Array sequence number conversion

Give you an array of integers  arr , Please replace each element in the array with their ordinal number after sorting .
The serial number represents how big an element is . The rules for serial numbers are as follows ：

• The serial number from 1 Numbered starting .
• The bigger an element is , So the bigger the serial number . If two elements are equal , So they have the same serial number .
• The serial number of each number should be as small as possible .

Input ：arr = [40,10,20,30]
Output ：[4,1,2,3]
explain ：40 It's the biggest element . 10 It's the smallest element . 20 It's the second smallest number . 30 It's the third smallest number .

Explain ：
After de reordering , Use a dictionary to record the sequence number of each number .

Log in and copy

class Solution:
    def arrayRankTransform(self, arr: List[int]) -> List[int]:
        sorted_arr = sorted(set(arr))
        d = {x:i for i,x in enumerate(sorted_arr,1)}
        return [d[x] for x in arr]

     

      
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There are two small details ,
The first detail is set It can also be used. sorted Function order .
sorted Function description ： according to iterable Returns a new sorted list .
Any iteratable object can be used sorted Sort , The result is a new sort list .

The second detail is enumerate You can specify the value from which the sequence number starts ,
enumerate(sorted_arr,1) This is from 1 Start counting .