581. Shortest Unsorted Continuous Subarray

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

这道题是要找出最短的子数组，如果此子数组按照升序排列，则整个数组按照升序排列。先用一个数组temp保存nums，然后对temp排序，然后用两个变量start和end去找两个数组出现不同之处的第一个位置和最后一个位置，最后返回end-start+1就是要找的数组长度。代码如下：

     int n = nums.length;         int[] temp = new int[n];         for (int i = 0; i < n; i++) temp[i] = nums[i];         Arrays.sort(temp);                  int start = 0;         while (start < n  && nums[start] == temp[start]) start++;                  int end = n - 1;         while (end > start  && nums[end] == temp[end]) end--;                  return end - start + 1;