# 1331 Rank Transform of an Array

Given an array of integers `arr`, replace each element with its rank.

The rank represents how large the element is. The rank has the following rules:

• Rank is an integer starting from 1.
• The larger the element, the larger the rank. If two elements are equal, their rank must be the same.
• Rank should be as small as possible.

Example 1:

``````Input: arr = [40,10,20,30]
Output: [4,1,2,3]
Explanation: 40 is the largest element. 10 is the smallest.
20 is the second smallest. 30 is the third smallest.
``````

Example 2:

``````Input: arr = [100,100,100]
Output: [1,1,1]
Explanation: Same elements share the same rank.
``````

Example 3:

``````Input: arr = [37,12,28,9,100,56,80,5,12]
Output: [5,3,4,2,8,6,7,1,3]
``````

Constraints:

• `0 <= arr.length <= 105`
• `-109 <= arr[i] <= 109`
 ``````1 2 3 4 5 `````` ``````class Solution: def arrayRankTransform(self, arr: List[int]) -> List[int]: ordered = sorted(list(set(arr))) d = {num: i+1 for i, num in enumerate(ordered)} return [d[a] for a in arr]``````