2366. Minimum Replacements to Sort the Array

题目

You are given a 0-indexed integer array nums. In one operation you can replace any element of the array with any two elements that sum to it.

• For example, consider nums = [5,6,7]. In one operation, we can replace nums[1] with 2 and 4 and convert nums to [5,2,4,7].

Return the minimum number of operations to make an array that is sorted in non-decreasing order.

Example 1:

Input: nums = [3,9,3]
Output: 2
Explanation: Here are the steps to sort the array in non-decreasing order:
- From [3,9,3], replace the 9 with 3 and 6 so the array becomes [3,3,6,3]
- From [3,3,6,3], replace the 6 with 3 and 3 so the array becomes [3,3,3,3,3]
There are 2 steps to sort the array in non-decreasing order. Therefore, we return 2.

Example 2:

Input: nums = [1,2,3,4,5]
Output: 0
Explanation: The array is already in non-decreasing order. Therefore, we return 0.

Constraints:

• 1 <= nums.length <= 105
• 1 <= nums[i] <= 109

代码

import math
class Solution(object):
def minimumReplacement(self, nums):
"""
:type nums: List[int]
:rtype: int
"""

ret = 0
cur_n = nums[-1]
for n in reversed(nums):
if n <= cur_n:
cur_n = n
continue
pieces = int(math.ceil(1.0 * n / cur_n))

ret += pieces - 1
cur_n = n // pieces

return ret

AC，收工！

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