找到最小长度未排序的子数组，进行排序，使整个数组排序

给定大小为n的未排序数组arr [0..n-1]，请找到最小长度的子数组arr [s..e]，以便对该子数组进行排序可以对整个数组进行排序。
例子：
1)如果输入数组为[10、12、20、30、25、40、32、31、35、50、60]，则程序应该能够找到子数组位于索引3和8之间。
2)如果输入数组为[0、1、15、25、6、7、30、40、50]，则程序应该能够找到子数组位于索引2和5之间。

解决方案：
1)查找候选未排序子数组
a)从左到右扫描，找到比下一个元素大的第一个元素。令s为该元素的索引。在上面的示例1中， s为3(索引为30)。
b)从右到左扫描，找到小于下一个元素(从右到左的顺序的下一个)的第一个元素(从右到左的顺序的第一个)。令e为此类元素的索引。在上面的示例1中，e为7(索引为31)。
2)检查对候选未排序子数组进行排序是否会使整个数组排序。如果不是，则在子数组中包含更多元素。
a)在arr [s..e]中找到最小值和最大值。设最小值和最大值为min和max 。 [30、25、40、32、31]的最小值和最大值分别为25和40。
b)在arr [0..s-1]中找到第一个元素(如果有)，该元素大于min ，将s更改为该元素的索引。上面的示例1中没有这样的元素。
c)在小于最大数的arr [e + 1..n-1]中找到最后一个元素(如果有)，将e更改为该元素的索引。在上面的示例1中，e更改为8(索引为35)
3)打印s和e 。
执行：

C++

// C++ program to find the Minimum length Unsorted Subarray,
// sorting which makes the complete array sorted
#include
using namespace std;
 
void printUnsorted(int arr[], int n)
{
int s = 0, e = n-1, i, max, min;
 
// step 1(a) of above algo
for (s = 0; s < n-1; s++)
{
    if (arr[s] > arr[s+1])
    break;
}
if (s == n-1)
{
    cout << "The complete array is sorted";
    return;
}
 
// step 1(b) of above algo
for(e = n - 1; e > 0; e--)
{
    if(arr[e] < arr[e-1])
    break;
}
 
// step 2(a) of above algo
max = arr[s]; min = arr[s];
for(i = s + 1; i <= e; i++)
{
    if(arr[i] > max)
    max = arr[i];
    if(arr[i] < min)
    min = arr[i];
}
 
// step 2(b) of above algo
for( i = 0; i < s; i++)
{
    if(arr[i] > min)
    {
    s = i;
    break;
    }    
}
 
// step 2(c) of above algo
for( i = n -1; i >= e+1; i--)
{
    if(arr[i] < max)
    {
    e = i;
    break;
    }
}
     
// step 3 of above algo
cout << "The unsorted subarray which"
     << " makes the given array" << endl
     << "sorted lies between the indees "
     << s << " and " << e;
return;
}
 
int main()
{
    int arr[] = {10, 12, 20, 30, 25,
                 40, 32, 31, 35, 50, 60};
    int arr_size = sizeof(arr)/sizeof(arr[0]);
    printUnsorted(arr, arr_size);
    getchar();
    return 0;
}
 
// This code is contributed
// by Akanksha Rai

C

// C program to find the Minimum length Unsorted Subarray,
// sorting which makes the complete array sorted
#include
  
void printUnsorted(int arr[], int n)
{
  int s = 0, e = n-1, i, max, min;  
  
  // step 1(a) of above algo
  for (s = 0; s < n-1; s++)
  {
    if (arr[s] > arr[s+1])
      break;
  }
  if (s == n-1)
  {
    printf("The complete array is sorted");
    return;
  }
  
  // step 1(b) of above algo
  for(e = n - 1; e > 0; e--)
  {
    if(arr[e] < arr[e-1])
      break;
  }
  
  // step 2(a) of above algo
  max = arr[s]; min = arr[s];
  for(i = s + 1; i <= e; i++)
  {
    if(arr[i] > max)
      max = arr[i];
    if(arr[i] < min)
      min = arr[i];
  }
  
  // step 2(b) of above algo
  for( i = 0; i < s; i++)
  {
    if(arr[i] > min)
    { 
      s = i;
      break;
    }     
  }
  
  // step 2(c) of above algo
  for( i = n -1; i >= e+1; i--)
  {
    if(arr[i] < max)
    {
      e = i;
      break;
    }
  } 
      
  // step 3 of above algo
  printf(" The unsorted subarray which makes the given array "
         " sorted lies between the indees %d and %d", s, e);
  return;
}
  
int main()
{
  int arr[] = {10, 12, 20, 30, 25, 40, 32, 31, 35, 50, 60};
  int arr_size = sizeof(arr)/sizeof(arr[0]);
  printUnsorted(arr, arr_size);
  getchar();
  return 0;
}

Java

// Java program to find the Minimum length Unsorted Subarray,
// sorting which makes the complete array sorted
class Main
{
    static void printUnsorted(int arr[], int n)
    {
      int s = 0, e = n-1, i, max, min;  
       
      // step 1(a) of above algo
      for (s = 0; s < n-1; s++)
      {
        if (arr[s] > arr[s+1])
          break;
      }
      if (s == n-1)
      {
        System.out.println("The complete array is sorted");
        return;
      }
       
      // step 1(b) of above algo
      for(e = n - 1; e > 0; e--)
      {
        if(arr[e] < arr[e-1])
          break;
      }
       
      // step 2(a) of above algo
      max = arr[s]; min = arr[s];
      for(i = s + 1; i <= e; i++)
      {
        if(arr[i] > max)
          max = arr[i];
        if(arr[i] < min)
          min = arr[i];
      }
       
      // step 2(b) of above algo
      for( i = 0; i < s; i++)
      {
        if(arr[i] > min)
        { 
          s = i;
          break;
        }     
      }
       
      // step 2(c) of above algo
      for( i = n -1; i >= e+1; i--)
      {
        if(arr[i] < max)
        {
          e = i;
          break;
        }
      } 
           
      // step 3 of above algo
      System.out.println(" The unsorted subarray which"+
                         " makes the given array sorted lies"+
                       "  between the indices "+s+" and "+e);
      return;
    }
       
    public static void main(String args[])
    {
      int arr[] = {10, 12, 20, 30, 25, 40, 32, 31, 35, 50, 60};
      int arr_size = arr.length;
      printUnsorted(arr, arr_size);
    }
}

Python3

# Python3 program to find the Minimum length Unsorted Subarray,
# sorting which makes the complete array sorted
def printUnsorted(arr, n):
    e = n-1
    # step 1(a) of above algo
    for s in range(0,n-1):
        if arr[s] > arr[s+1]:
            break
         
    if s == n-1:
        print ("The complete array is sorted")
        exit()
 
    # step 1(b) of above algo
    e= n-1
    while e > 0:
        if arr[e] < arr[e-1]:
            break
        e -= 1
 
    # step 2(a) of above algo
    max = arr[s]
    min = arr[s]
    for i in range(s+1,e+1):
        if arr[i] > max:
            max = arr[i]
        if arr[i] < min:
            min = arr[i]
             
    # step 2(b) of above algo
    for i in range(s):
        if arr[i] > min:
            s = i
            break
 
    # step 2(c) of above algo
    i = n-1
    while i >= e+1:
        if arr[i] < max:
            e = i
            break
        i -= 1
     
    # step 3 of above algo
    print ("The unsorted subarray which makes the given array")
    print ("sorted lies between the indexes %d and %d"%( s, e))
 
arr = [10, 12, 20, 30, 25, 40, 32, 31, 35, 50, 60]
arr_size = len(arr)
printUnsorted(arr, arr_size)
 
# This code is contributed by Shreyanshi Arun

C#

// C# program to find the Minimum length Unsorted Subarray,
// sorting which makes the complete array sorted
 
using System;
 
class GFG
{
    static void printUnsorted(int []arr, int n)
    {
    int s = 0, e = n-1, i, max, min;
         
    // step 1(a) of above algo
    for (s = 0; s < n-1; s++)
    {
        if (arr[s] > arr[s+1])
        break;
    }
    if (s == n-1)
    {
        Console.Write("The complete " +
                            "array is sorted");
        return;
    }
         
    // step 1(b) of above algo
    for(e = n - 1; e > 0; e--)
    {
        if(arr[e] < arr[e-1])
        break;
    }
         
    // step 2(a) of above algo
    max = arr[s]; min = arr[s];
     
    for(i = s + 1; i <= e; i++)
    {
        if(arr[i] > max)
            max = arr[i];
         
        if(arr[i] < min)
            min = arr[i];
    }
         
    // step 2(b) of above algo
    for( i = 0; i < s; i++)
    {
        if(arr[i] > min)
        {
            s = i;
            break;
        }    
    }
         
    // step 2(c) of above algo
    for( i = n -1; i >= e+1; i--)
    {
        if(arr[i] < max)
        {
            e = i;
            break;
        }
    }
             
    // step 3 of above algo
    Console.Write(" The unsorted subarray which"+
            " makes the given array sorted lies \n"+
              " between the indices "+s+" and "+e);
    return;
    }
         
    public static void Main()
    {
        int []arr = {10, 12, 20, 30, 25, 40,
                                32, 31, 35, 50, 60};
        int arr_size = arr.Length;
         
        printUnsorted(arr, arr_size);
    }
}
 
// This code contributed by Sam007

PHP

 $arr[$s + 1])
        break;
    }
    if ($s == $n - 1)
    {
        echo "The complete array is sorted";
        return;
    }
     
    // step 1(b) of above algo
    for($e = $n - 1; $e > 0; $e--)
    {
        if($arr[$e] < $arr[$e - 1])
        break;
    }
     
    // step 2(a) of above algo
    $max = $arr[$s];
    $min = $arr[$s];
    for($i = $s + 1; $i <= $e; $i++)
    {
        if($arr[$i] > $max)
            $max = $arr[$i];
        if($arr[$i] < $min)
            $min = $arr[$i];
    }
     
    // step 2(b) of above algo
    for( $i = 0; $i < $s; $i++)
    {
        if($arr[$i] > $min)
        {
            $s = $i;
            break;
        }    
    }
     
    // step 2(c) of above algo
    for( $i = $n - 1; $i >= $e + 1; $i--)
    {
        if($arr[$i] < $max)
        {
            $e = $i;
            break;
        }
    }
         
    // step 3 of above algo
    echo " The unsorted subarray which makes " .
                     "the given array " . "\n" .
            " sorted lies between the indees " .
                              $s . " and " . $e;
    return;
}
 
// Driver code
$arr = array(10, 12, 20, 30, 25, 40,
             32, 31, 35, 50, 60);
$arr_size = sizeof($arr);
printUnsorted($arr, $arr_size);
 
// This code is contributed
// by ChitraNayal
?>

Javascript

 
// Javascript program to find the Minimum length Unsorted Subarray, 
// sorting which makes the complete array sorted
     
    function printUnsorted(arr,n)
    {
        let s = 0, e = n-1, i, max, min;
        // step 1(a) of above algo
        for (s = 0; s < n-1; s++)
        {
            if (arr[s] > arr[s+1])
                break;
        }
        if (s == n-1)
        {
            document.write("The complete array is sorted");
            return;
        }
        // step 1(b) of above algo
        for(e = n - 1; e > 0; e--)
        {
            if(arr[e] < arr[e-1])
                break;
        }
        // step 2(a) of above algo
        max = arr[s]; min = arr[s];
        for(i = s + 1; i <= e; i++)
        {
            if(arr[i] > max)
                max = arr[i];
            if(arr[i] < min)
                min = arr[i];
        }
        // step 2(b) of above algo
        for( i = 0; i < s; i++)
        {
            if(arr[i] > min)
            {
                s = i;
                break;
            }
        }
        // step 2(c) of above algo
        for( i = n -1; i >= e+1; i--)
        {
            if(arr[i] < max)
            {
                e = i;
                break;
            }
        }
        // step 3 of above algo
        document.write(" The unsorted subarray which"+
                         " makes the given array sorted lies"+
                       "  between the indees "+s+" and "+e);
        return;
    }
    let arr=[10, 12, 20, 30, 25, 40, 32, 31, 35, 50, 60];
    let arr_size = arr.length;
    printUnsorted(arr, arr_size);
     
    // This code is contributed by avanitrachhadiya2155
     

输出 ：

The unsorted subarray which makes the given array 
sorted lies between the indees 3 and 8

时间复杂度： O(n)