【leetcode】1331. Rank Transform of an Array

题目如下：

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

解题思路：很简单的题目，可以先对arr去重排序，然后遍历arr，求出每个元素在排序后的arr的下标即可。

代码如下：

class Solution(object):
    def arrayRankTransform(self, arr):
        """
        :type arr: List[int]
        :rtype: List[int]
        """
        sort_arr = sorted(list(set(arr)))
        import bisect
        res = []
        for i in arr:
            inx = bisect.bisect_left(sort_arr,i)
            res.append(inx + 1)
        return res