## Algorithm

Problem Name: 581. Shortest Unsorted Continuous Subarray

Given an integer array `nums`, 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.

Return the shortest such subarray and output its length.

Example 1:

```Input: nums = [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.
```

Example 2:

```Input: nums = [1,2,3,4]
Output: 0
```

Example 3:

```Input: nums = [1]
Output: 0
```

Constraints:

• `1 <= nums.length <= 104`
• `-105 <= nums[i] <= 105`

## Code Examples

### #1 Code Example with Java Programming

```Code - Java Programming```

``````
class Solution {
public int findUnsortedSubarray(int[] nums) {
Stack stack = new Stack<>();
int start = nums.length;
for (int i = 0; i  <  nums.length; i++) {
while (!stack.isEmpty() && nums[stack.peek()] > nums[i]) {
start = Math.min(start, stack.pop());
}
stack.push(i);
}
stack.clear();
int end = 0;
for (int i = nums.length - 1; i >= 0; i--) {
while (!stack.isEmpty() && nums[stack.peek()]  <  nums[i]) {
end = Math.max(end, stack.pop());
}
stack.push(i);
}
return end - start > 0 ? end - start + 1 : 0;
}
}
``````
Copy The Code &

Input

cmd
nums = [2,6,4,8,10,9,15]

Output

cmd
5

### #2 Code Example with Javascript Programming

```Code - Javascript Programming```

``````
const findUnsortedSubarray = function(nums) {
let stack = []
let left = nums.length
let right = 0
for(let i = 0; i  <  nums.length; i++) {
while(stack.length > 0 && nums[stack[stack.length - 1]] > nums[i]) {
left = Math.min(left, stack.pop())
}
stack.push(i)
}
stack = []
for(let i = nums.length - 1; i >= 0; i--) {
while(stack.length > 0 && nums[stack[stack.length - 1]]  <  nums[i] ) {
right = Math.max(right, stack.pop())
}
stack.push(i)
}

return right > left ? right - left + 1: 0
};
``````
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Input

cmd
nums = [2,6,4,8,10,9,15]

Output

cmd
5

### #3 Code Example with Python Programming

```Code - Python Programming```

``````
class Solution:
def findUnsortedSubarray(self, nums: List[int]) -> int:
arr = sorted(nums)
i = 0
for i in range(len(arr)):
if arr[i] != nums[i]:
for j in range(len(arr) - 1, -1, -1):
if arr[j] != nums[j]:
return j - i + 1
return 0
``````
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Input

cmd
nums = [1,2,3,4]

### #4 Code Example with C# Programming

```Code - C# Programming```

``````
using System;

namespace LeetCode
{
public class _0581_ShortestUnsortedContinuousSubarray
{
public int FindUnsortedSubarray(int[] nums)
{
int min = int.MaxValue, max = int.MinValue;
var flag = false;
for (int i = 1; i  <  nums.Length; i++)
{
if (nums[i] < nums[i - 1])
flag = true;
if (flag)
min = Math.Min(min, nums[i]);
}
flag = false;
for (int i = nums.Length - 2; i >= 0; i--)
{
if (nums[i] > nums[i + 1])
flag = true;
if (flag)
max = Math.Max(max, nums[i]);
}

int l, r;
for (l = 0; l  <  nums.Length; l++)
if (min < nums[l])
break;
for (r = nums.Length - 1; r >= 0; r--)
if (max > nums[r])
break;

return r >= l ? r - l + 1 : 0;
}
}
}
``````
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Input

cmd
nums = [1,2,3,4]