leetcode1331. Rank Transform of an Array

Posted 2021-03-13 seyjs

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