1574. Shortest Subarray to be Removed to Make Array Sorted

https://leetcode.com/problems/shortest-subarray-to-be-removed-to-make-array-sorted

Description

Given an integer array arr, remove a subarray (can be empty) from arr such that the remaining elements in arr are non-decreasing.

A subarray is a contiguous subsequence of the array.

Return the length of the shortest subarray to remove.

Example 1:

**Input:** arr = [1,2,3,10,4,2,3,5]
**Output:** 3
**Explanation:** The shortest subarray we can remove is [10,4,2] of length 3. The remaining elements after that will be [1,2,3,3,5] which are sorted.
Another correct solution is to remove the subarray [3,10,4].

Example 2:

**Input:** arr = [5,4,3,2,1]
**Output:** 4
**Explanation:** Since the array is strictly decreasing, we can only keep a single element. Therefore we need to remove a subarray of length 4, either [5,4,3,2] or [4,3,2,1].

Example 3:

**Input:** arr = [1,2,3]
**Output:** 0
**Explanation:** The array is already non-decreasing. We do not need to remove any elements.

Example 4:

**Input:** arr = [1]
**Output:** 0

Constraints:

• 1 <= arr.length <= 10^5

• 0 <= arr[i] <= 10^9

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