Description
Given an integer array nums, return an integer array counts where counts[i] is the number of smaller elements to the right of nums[i].
Example 1:
Input: nums = [5,2,6,1] Output: [2,1,1,0] Explanation: To the right of 5 there are 2 smaller elements (2 and 1). To the right of 2 there is only 1 smaller element (1). To the right of 6 there is 1 smaller element (1). To the right of 1 there is 0 smaller element.
Example 2:
Input: nums = [-1] Output: [0]
Example 3:
Input: nums = [-1,-1] Output: [0,0]
Constraints:
1 <= nums.length <= 105-104 <= nums[i] <= 104
Solution
Python3
from sortedcontainers import SortedList
class Solution:
def countSmaller(self, nums: List[int]) -> List[int]:
n = len(nums)
res = [0] * n
sl = SortedList([nums[-1]])
for i in range(n - 2, -1, -1):
index = sl.bisect(nums[i] - 1)
res[i] = index
sl.add(nums[i])
return res