题目
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.
- T he 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.
解题思路
给所有的数去重再排序，用字典记录rank，在遍历数组，用rank替换。
代码
class Solution:
def arrayRankTransform(self, arr: List[int]) -> List[int]:
dic = {}
rank = 1
for n in sorted(set(arr)):
dic[n] = rank
rank += 1
for i in range(len(arr)):
arr[i] = dic[arr[i]]
return arr
