1331. Rank Transform of an Array
## 思路
先用sort过的arr建 num -> rank 的HashTable
再把arr转成rank
## Code
```python
class Solution:
def arrayRankTransform(self, arr: List[int]) -> List[int]:
table = {}
rank = 1
for num in sorted(arr):
if num not in table:
table[num] = rank
rank += 1
return [table[num] for num in arr]
```