LeetCode-Shortest Unsorted Continuous Subarray

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Description：
Given an integer array, you need to find one continuous subarray that if you only sort this subarray in ascending order, then the whole array will be sorted in ascending order, too.

You need to find the shortest such subarray and output its length.

Example 1:

Input: [2, 6, 4, 8, 10, 9, 15]
Output: 5
Explanation: You need to sort [6, 4, 8, 10, 9] in ascending order to make the whole array sorted in ascending order.

Note:

• Then length of the input array is in range [1, 10,000].
• The input array may contain duplicates, so ascending order here means <=.

题意：给定一个一维数组，要求找到一个连续的子数组，将这个子数组排序后，整个数组是有序的，返回找到的最短的连续子数组；

解法：我们的任务是最终要完成整个数组的排序，数组中已经有部分序列数有序的，我们只需要将无序的那部分重新排序即可；因此，可以对照排序后的原数组，从首尾找到与排序后不相等的第一个元素的位置，这两个位置之间就是我们需要进行排序的位置；

class Solution {
    public int findUnsortedSubarray(int[] nums) {
        int[] temp = Arrays.copyOf(nums, nums.length);
        Arrays.sort(temp);
        int st = 0;
        int ed = nums.length - 1;
        while (st < nums.length && temp[st] == nums[st]) st++;
        while (ed >= 0 && temp[ed] == nums[ed]) ed--;
        return ed <= st ? 0 : ed - st + 1;
    }
}