leetcode-1331 - Rank Transform of an Array

動機

先做這題，再看1632會比較有感覺

Problem

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:

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

Example 1:

rInput: arr = [40,10,20,30]rOutput: [4,1,2,3]rExplanation: 40 is the largest element. 10 is the smallest. 20 is the second smallest. 30 is the third smallest.

Example 2:

rInput: arr = [100,100,100]rOutput: [1,1,1]rExplanation: Same elements share the same rank.r

Example 3:

rInput: arr = [37,12,28,9,100,56,80,5,12]rOutput: [5,3,4,2,8,6,7,1,3]r

Constraints:

rt
• 0 <= arr.length <= 105
rt
• -109 <= arr[i] <= 109
r

Sol

存位置設定成一樣的rank

class Solution:
    def arrayRankTransform(self, arr: List[int]) -> List[int]:
        tbl = defaultdict(list)
        for (i,n) in enumerate(arr):
            tbl[n].append(i)
        
        rank = 1
        for k in sorted(tbl.keys()):
            for i in tbl[k]:
                arr[i] = rank
            rank+=1
        return arr