
Given an integer array nums , you need to find one continuous subarray such that if you only sort this subarray in non-decreasing order, then the whole array will be sorted in non-decreasing order.
Return the shortest such subarray and output its length .
1 <= nums.length <= 10 ^4-10 ^5 <= nums[i] <= 10 ^5Follow up: Can you solve it in O(n) time complexity?