مجموع الحد الأدنى والحد الأقصى لجميع المصفوفات الفرعية بالحجم k.

بالنظر إلى مجموعة من الأعداد الصحيحة الموجبة والسالبة، تكون المهمة هي حساب مجموع العناصر الدنيا والقصوى لجميع المصفوفات الفرعية ذات الحجم k.

أمثلة: 

مدخل : arr[] = {2 5 -1 7 -3 -1 -2}
ك = 4
الإخراج : 18
توضيح : المصفوفات الفرعية بالحجم 4 هي:
{2 5 -1 7} دقيقة + حد أقصى = -1 + 7 = 6
{5 -1 7 -3} دقيقة + حد أقصى = -3 + 7 = 4
{-1 7 -3 -1} دقيقة + حد أقصى = -3 + 7 = 4
{7 -3 -1 -2} دقيقة + حد أقصى = -3 + 7 = 4

المصفوفات الفرعية المفقودة -

{2 -1 7 -3}
{2 7 -3 -1}
{2 -3 -1 -2}
{5 7 -3 -1}
{5 -3 -1 -2}
وغيرها القليل - لماذا لم يتم أخذها بعين الاعتبار؟؟
مع الأخذ في الاعتبار أن المصفوفات المفقودة تأتي بنتيجة 27

مجموع الحد الأدنى والحد الأقصى = 6 + 4 + 4 + 4 = 18

هذه المشكلة هي في الأساس امتداد للمشكلة أدناه. 
الحد الأقصى لجميع المصفوفات الفرعية بالحجم k 

النهج الساذج:

قم بتشغيل حلقتين لإنشاء جميع المصفوفات الفرعية ثم اختر جميع المصفوفات الفرعية بالحجم k وابحث عن القيم القصوى والدنيا. وأخيرًا، قم بإرجاع مجموع العناصر القصوى والدنيا. 

C++
   // C++ program to find sum of all minimum and maximum   // elements Of Sub-array Size k.   #include          using     namespace     std  ;   // Returns sum of min and max element of all subarrays   // of size k   int     SumOfKsubArray  (  int     arr  []     int     N       int     k  )   {      // To store final answer      int     sum     =     0  ;      // Find all subarray      for     (  int     i     =     0  ;     i      <     N  ;     i  ++  )     {      // To store length of subarray      int     length     =     0  ;      for     (  int     j     =     i  ;     j      <     N  ;     j  ++  )     {      // Increment the length      length  ++  ;      // When there is subarray of size k      if     (  length     ==     k  )     {      // To store maximum and minimum element      int     maxi     =     INT_MIN  ;      int     mini     =     INT_MAX  ;      for     (  int     m     =     i  ;     m      <=     j  ;     m  ++  )     {      // Find maximum and minimum element      maxi     =     max  (  maxi       arr  [  m  ]);      mini     =     min  (  mini       arr  [  m  ]);      }      // Add maximum and minimum element in sum      sum     +=     maxi     +     mini  ;      }      }      }      return     sum  ;   }   // Driver program to test above functions   int     main  ()   {      int     arr  []     =     {     2       5       -1       7       -3       -1       -2     };      int     N     =     sizeof  (  arr  )     /     sizeof  (  arr  [  0  ]);      int     k     =     4  ;      cout      < <     SumOfKsubArray  (  arr       N       k  );      return     0  ;   }   
Java
   // Java program to find sum of all minimum and maximum   // elements Of Sub-array Size k.   import     java.util.Arrays  ;   class   GFG     {      // Returns sum of min and max element of all subarrays      // of size k      static     int     SumOfKsubArray  (  int  []     arr       int     N       int     k  )     {      // To store the final answer      int     sum     =     0  ;      // Find all subarrays      for     (  int     i     =     0  ;     i      <     N  ;     i  ++  )     {      // To store the length of the subarray      int     length     =     0  ;      for     (  int     j     =     i  ;     j      <     N  ;     j  ++  )     {      // Increment the length      length  ++  ;      // When there is a subarray of size k      if     (  length     ==     k  )     {      // To store the maximum and minimum element      int     maxi     =     Integer  .  MIN_VALUE  ;      int     mini     =     Integer  .  MAX_VALUE  ;      for     (  int     m     =     i  ;     m      <=     j  ;     m  ++  )     {      // Find the maximum and minimum element      maxi     =     Math  .  max  (  maxi       arr  [  m  ]  );      mini     =     Math  .  min  (  mini       arr  [  m  ]  );      }      // Add the maximum and minimum element to the sum      sum     +=     maxi     +     mini  ;      }      }      }      return     sum  ;      }      // Driver program to test above functions      public     static     void     main  (  String  []     args  )     {      int  []     arr     =     {  2       5       -  1       7       -  3       -  1       -  2  };      int     N     =     arr  .  length  ;      int     k     =     4  ;      System  .  out  .  println  (  SumOfKsubArray  (  arr       N       k  ));      }   }   //This code is contributed by Vishal Dhaygude   
Python
   # Returns sum of min and max element of all subarrays   # of size k   def   sum_of_k_subarray  (  arr     N     k  ):   # To store final answer   sum   =   0   # Find all subarrays   for   i   in   range  (  N  ):   # To store length of subarray   length   =   0   for   j   in   range  (  i     N  ):   # Increment the length   length   +=   1   # When there is a subarray of size k   if   length   ==   k  :   # To store maximum and minimum element   maxi   =   float  (  '-inf'  )   mini   =   float  (  'inf'  )   for   m   in   range  (  i     j   +   1  ):   # Find maximum and minimum element   maxi   =   max  (  maxi     arr  [  m  ])   mini   =   min  (  mini     arr  [  m  ])   # Add maximum and minimum element to sum   sum   +=   maxi   +   mini   return   sum   # Driver program to test above function   def   main  ():   arr   =   [  2     5     -  1     7     -  3     -  1     -  2  ]   N   =   len  (  arr  )   k   =   4   print  (  sum_of_k_subarray  (  arr     N     k  ))   if   __name__   ==   '__main__'  :   main  ()   
C#
   using     System  ;   class     Program     {      // Returns sum of min and max element of all subarrays      // of size k      static     int     SumOfKSubArray  (  int  []     arr       int     N       int     k  )      {      // To store the final answer      int     sum     =     0  ;      // Find all subarrays      for     (  int     i     =     0  ;     i      <     N  ;     i  ++  )     {      // To store the length of subarray      int     length     =     0  ;      for     (  int     j     =     i  ;     j      <     N  ;     j  ++  )     {      // Increment the length      length  ++  ;      // When there is a subarray of size k      if     (  length     ==     k  )     {      // To store the maximum and minimum      // element      int     maxi     =     int  .  MinValue  ;      int     mini     =     int  .  MaxValue  ;      for     (  int     m     =     i  ;     m      <=     j  ;     m  ++  )     {      // Find maximum and minimum element      maxi     =     Math  .  Max  (  maxi       arr  [  m  ]);      mini     =     Math  .  Min  (  mini       arr  [  m  ]);      }      // Add maximum and minimum element in      // sum      sum     +=     maxi     +     mini  ;      }      }      }      return     sum  ;      }      // Driver program to test above functions      static     void     Main  ()      {      int  []     arr     =     {     2       5       -  1       7       -  3       -  1       -  2     };      int     N     =     arr  .  Length  ;      int     k     =     4  ;      Console  .  WriteLine  (  SumOfKSubArray  (  arr       N       k  ));      }   }   
JavaScript
   // JavaScript program to find sum of all minimum and maximum   // elements of sub-array size k.   // Returns sum of min and max element of all subarrays   // of size k   function     SumOfKsubArray  (  arr       N       k  )     {      // To store final answer      let     sum     =     0  ;      // Find all subarray      for     (  let     i     =     0  ;     i      <     N  ;     i  ++  )     {      // To store length of subarray      let     length     =     0  ;      for     (  let     j     =     i  ;     j      <     N  ;     j  ++  )     {      // Increment the length      length  ++  ;      // When there is subarray of size k      if     (  length     ===     k  )     {      // To store maximum and minimum element      let     maxi     =     Number  .  MIN_SAFE_INTEGER  ;      let     mini     =     Number  .  MAX_SAFE_INTEGER  ;      for     (  let     m     =     i  ;     m      <=     j  ;     m  ++  )     {      // Find maximum and minimum element      maxi     =     Math  .  max  (  maxi       arr  [  m  ]);      mini     =     Math  .  min  (  mini       arr  [  m  ]);      }      // Add maximum and minimum element in sum      sum     +=     maxi     +     mini  ;      }      }      }      return     sum  ;   }   // Driver program to test above function   const     arr     =     [  2       5       -  1       7       -  3       -  1       -  2  ];   const     N     =     arr  .  length  ;   const     k     =     4  ;   console  .  log  (  SumOfKsubArray  (  arr       N       k  ));   

الإخراج
18 

تعقيد الوقت: على 2 *k) لأن حلقتين للعثور على كل المصفوفة الفرعية وحلقة واحدة للعثور على الحد الأقصى والحد الأدنى من العناصر في المصفوفة الفرعية بالحجم k
المساحة المساعدة: O(1) لأنه لم يتم استخدام مساحة إضافية

الطريقة الثانية (باستخدام MultiSet):

الفكرة هي استخدام بنية بيانات Multiset ومفهوم النافذة المنزلقة.

  • أولا نقوم بإنشاء multiset زوج من {numberindex} لأن الفهرس سيساعدنا في إزالة العنصر i والانتقال إلى النافذة التالية بالحجم ك .
  • ثانيا لدينا أنا و ي وهي عبارة عن مؤشر خلفي وأمامي يستخدم للحفاظ على النافذة.
  • قم بالاجتياز عبر المصفوفة وأدخلها في زوج متعدد المجموعات من {numberindex} وتحقق أيضًا من حجم النافذة بمجرد أن تصبح مساوية لـ ك ابدأ هدفك الأساسي، أي العثور على مجموع العناصر القصوى والدنيا.
  • ثم قم بمسح رقم الفهرس رقم من المجموعة وحرك المؤشر إلى الموقع التالي، أي نافذة جديدة بالحجم ك.

تطبيق:

C++
   // C++ program to find sum of all minimum and maximum   // elements Of Sub-array Size k.   #include          using     namespace     std  ;   // Returns sum of min and max element of all subarrays   // of size k   int     SumOfKsubArray  (  int     arr  []     int     n       int     k  )   {      int     sum     =     0  ;     // to store our final sum      // multiset because nos. could be repeated      // multiset pair is {numberindex}      multiset   <  pair   <  int       int  >     >     ms  ;      int     i     =     0  ;     // back pointer      int     j     =     0  ;     // front pointer      while     (  j      <     n     &&     i      <     n  )     {      ms  .  insert  (      {     arr  [  j  ]     j     });     // inserting {numberindex}      // front pointer - back pointer + 1 is for checking      // window size      int     windowSize     =     j     -     i     +     1  ;      // Once they become equal start what we need to do      if     (  windowSize     ==     k  )     {      // extracting first since set is always in      // sorted ascending order      int     mini     =     ms  .  begin  ()  ->  first  ;      // extracting last element aka beginning from      // last (numbers extraction)      int     maxi     =     ms  .  rbegin  ()  ->  first  ;      // adding summation of maximum & minimum element      // of each subarray of k into final sum      sum     +=     (  maxi     +     mini  );      // erasing the ith index element from set as it      // won't appaer in next window of size k      ms  .  erase  ({     arr  [  i  ]     i     });      // increasing back pointer for next window of      // size k;      i  ++  ;      }      j  ++  ;     // always increments front pointer      }      return     sum  ;   }   // Driver program to test above functions   int     main  ()   {      int     arr  []     =     {     2       5       -1       7       -3       -1       -2     };      int     n     =     sizeof  (  arr  )     /     sizeof  (  arr  [  0  ]);      int     k     =     4  ;      cout      < <     SumOfKsubArray  (  arr       n       k  );      return     0  ;   }   

الإخراج
18 

تعقيد الوقت: O(nlogk)
المساحة المساعدة: O(k)

الطريقة الثالثة (فعالة باستخدام Dequeue):

الفكرة هي استخدام بنية بيانات Dequeue ومفهوم النافذة المنزلقة. نقوم بإنشاء قائمتين فارغتين من قوائم الانتظار ذات النهايتين بالحجم k ('S' 'G') اللتين تخزنان فقط فهارس عناصر النافذة الحالية التي ليست عديمة الفائدة. يكون العنصر عديم الفائدة إذا لم يكن الحد الأقصى أو الأدنى للمصفوفات الفرعية التالية. 

C++
   // C++ program to find sum of all minimum and maximum   // elements Of Sub-array Size k.   #include       using     namespace     std  ;   // Returns sum of min and max element of all subarrays   // of size k   int     SumOfKsubArray  (  int     arr  []          int     n          int     k  )   {      int     sum     =     0  ;     // Initialize result      // The queue will store indexes of useful elements      // in every window      // In deque 'G' we maintain decreasing order of      // values from front to rear      // In deque 'S' we maintain increasing order of      // values from front to rear      deque   <     int     >     S  (  k  )     G  (  k  );      // Process first window of size K      int     i     =     0  ;      for     (  i     =     0  ;     i      <     k  ;     i  ++  )      {      // Remove all previous greater elements      // that are useless.      while     (     (  !  S  .  empty  ())     &&     arr  [  S  .  back  ()]     >=     arr  [  i  ])      S  .  pop_back  ();     // Remove from rear      // Remove all previous smaller that are elements      // are useless.      while     (     (  !  G  .  empty  ())     &&     arr  [  G  .  back  ()]      <=     arr  [  i  ])      G  .  pop_back  ();     // Remove from rear      // Add current element at rear of both deque      G  .  push_back  (  i  );      S  .  push_back  (  i  );      }      // Process rest of the Array elements      for     (     ;     i      <     n  ;     i  ++     )      {      // Element at the front of the deque 'G' & 'S'      // is the largest and smallest      // element of previous window respectively      sum     +=     arr  [  S  .  front  ()]     +     arr  [  G  .  front  ()];      // Remove all elements which are out of this      // window      if     (     !  S  .  empty  ()     &&     S  .  front  ()     ==     i     -     k  )      S  .  pop_front  ();      if     (     !  G  .  empty  ()     &&     G  .  front  ()     ==     i     -     k  )      G  .  pop_front  ();      // remove all previous greater element that are      // useless      while     (     (  !  S  .  empty  ())     &&     arr  [  S  .  back  ()]     >=     arr  [  i  ])      S  .  pop_back  ();     // Remove from rear      // remove all previous smaller that are elements      // are useless      while     (     (  !  G  .  empty  ())     &&     arr  [  G  .  back  ()]      <=     arr  [  i  ])      G  .  pop_back  ();     // Remove from rear      // Add current element at rear of both deque      G  .  push_back  (  i  );      S  .  push_back  (  i  );      }      // Sum of minimum and maximum element of last window      sum     +=     arr  [  S  .  front  ()]     +     arr  [  G  .  front  ()];      return     sum  ;   }   // Driver program to test above functions   int     main  ()   {      int     arr  []     =     {  2       5       -1       7       -3       -1       -2  }     ;      int     n     =     sizeof  (  arr  )  /  sizeof  (  arr  [  0  ]);      int     k     =     4  ;      cout      < <     SumOfKsubArray  (  arr       n       k  )     ;      return     0  ;   }   
Java
   // Java program to find sum of all minimum and maximum    // elements Of Sub-array Size k.    import     java.util.Deque  ;   import     java.util.LinkedList  ;   public     class   Geeks     {      // Returns sum of min and max element of all subarrays       // of size k       public     static     int     SumOfKsubArray  (  int     arr  []          int     k  )         {         int     sum     =     0  ;     // Initialize result           // The queue will store indexes of useful elements       // in every window       // In deque 'G' we maintain decreasing order of       // values from front to rear       // In deque 'S' we maintain increasing order of       // values from front to rear       Deque   <  Integer  >     S  =  new     LinkedList   <>  ()  G  =  new     LinkedList   <>  ();      // Process first window of size K       int     i     =     0  ;         for     (  i     =     0  ;     i      <     k  ;     i  ++  )         {         // Remove all previous greater elements       // that are useless.       while     (     !  S  .  isEmpty  ()     &&     arr  [  S  .  peekLast  ()  ]     >=     arr  [  i  ]  )         S  .  removeLast  ();     // Remove from rear           // Remove all previous smaller that are elements       // are useless.       while     (     !  G  .  isEmpty  ()     &&     arr  [  G  .  peekLast  ()  ]      <=     arr  [  i  ]  )         G  .  removeLast  ();     // Remove from rear           // Add current element at rear of both deque       G  .  addLast  (  i  );         S  .  addLast  (  i  );         }             // Process rest of the Array elements       for     (     ;     i      <     arr  .  length  ;     i  ++     )         {         // Element at the front of the deque 'G' & 'S'       // is the largest and smallest       // element of previous window respectively       sum     +=     arr  [  S  .  peekFirst  ()  ]     +     arr  [  G  .  peekFirst  ()  ]  ;             // Remove all elements which are out of this       // window       while     (     !  S  .  isEmpty  ()     &&     S  .  peekFirst  ()      <=     i     -     k  )         S  .  removeFirst  ();         while     (     !  G  .  isEmpty  ()     &&     G  .  peekFirst  ()      <=     i     -     k  )         G  .  removeFirst  ();             // remove all previous greater element that are       // useless       while     (     !  S  .  isEmpty  ()     &&     arr  [  S  .  peekLast  ()  ]     >=     arr  [  i  ]  )         S  .  removeLast  ();     // Remove from rear           // remove all previous smaller that are elements       // are useless       while     (     !  G  .  isEmpty  ()     &&     arr  [  G  .  peekLast  ()  ]      <=     arr  [  i  ]  )         G  .  removeLast  ();     // Remove from rear           // Add current element at rear of both deque       G  .  addLast  (  i  );         S  .  addLast  (  i  );         }             // Sum of minimum and maximum element of last window       sum     +=     arr  [  S  .  peekFirst  ()  ]     +     arr  [  G  .  peekFirst  ()  ]  ;             return     sum  ;         }         public     static     void     main  (  String     args  []  )         {      int     arr  []     =     {  2       5       -  1       7       -  3       -  1       -  2  }     ;         int     k     =     4  ;         System  .  out  .  println  (  SumOfKsubArray  (  arr       k  ));      }   }   //This code is contributed by Gaurav Tiwari   
Python
   # Python3 program to find Sum of all minimum and maximum    # elements Of Sub-array Size k.   from   collections   import   deque   # Returns Sum of min and max element of all subarrays   # of size k   def   SumOfKsubArray  (  arr     n      k  ):   Sum   =   0   # Initialize result   # The queue will store indexes of useful elements   # in every window   # In deque 'G' we maintain decreasing order of   # values from front to rear   # In deque 'S' we maintain increasing order of   # values from front to rear   S   =   deque  ()   G   =   deque  ()   # Process first window of size K   for   i   in   range  (  k  ):   # Remove all previous greater elements   # that are useless.   while   (   len  (  S  )   >   0   and   arr  [  S  [  -  1  ]]   >=   arr  [  i  ]):   S  .  pop  ()   # Remove from rear   # Remove all previous smaller that are elements   # are useless.   while   (   len  (  G  )   >   0   and   arr  [  G  [  -  1  ]]    <=   arr  [  i  ]):   G  .  pop  ()   # Remove from rear   # Add current element at rear of both deque   G  .  append  (  i  )   S  .  append  (  i  )   # Process rest of the Array elements   for   i   in   range  (  k     n  ):   # Element at the front of the deque 'G' & 'S'   # is the largest and smallest   # element of previous window respectively   Sum   +=   arr  [  S  [  0  ]]   +   arr  [  G  [  0  ]]   # Remove all elements which are out of this   # window   while   (   len  (  S  )   >   0   and   S  [  0  ]    <=   i   -   k  ):   S  .  popleft  ()   while   (   len  (  G  )   >   0   and   G  [  0  ]    <=   i   -   k  ):   G  .  popleft  ()   # remove all previous greater element that are   # useless   while   (   len  (  S  )   >   0   and   arr  [  S  [  -  1  ]]   >=   arr  [  i  ]):   S  .  pop  ()   # Remove from rear   # remove all previous smaller that are elements   # are useless   while   (   len  (  G  )   >   0   and   arr  [  G  [  -  1  ]]    <=   arr  [  i  ]):   G  .  pop  ()   # Remove from rear   # Add current element at rear of both deque   G  .  append  (  i  )   S  .  append  (  i  )   # Sum of minimum and maximum element of last window   Sum   +=   arr  [  S  [  0  ]]   +   arr  [  G  [  0  ]]   return   Sum   # Driver program to test above functions   arr  =  [  2     5     -  1     7     -  3     -  1     -  2  ]   n   =   len  (  arr  )   k   =   4   print  (  SumOfKsubArray  (  arr     n     k  ))   # This code is contributed by mohit kumar   
C#
   // C# program to find sum of all minimum and maximum    // elements Of Sub-array Size k.    using     System  ;   using     System.Collections.Generic  ;   class     Geeks   {      // Returns sum of min and max element of all subarrays       // of size k       public     static     int     SumOfKsubArray  (  int     []  arr          int     k  )         {         int     sum     =     0  ;     // Initialize result       // The queue will store indexes of useful elements       // in every window       // In deque 'G' we maintain decreasing order of       // values from front to rear       // In deque 'S' we maintain increasing order of       // values from front to rear       List   <  int  >     S     =     new     List   <  int  >  ();      List   <  int  >     G     =     new     List   <  int  >  ();      // Process first window of size K       int     i     =     0  ;         for     (  i     =     0  ;     i      <     k  ;     i  ++  )         {         // Remove all previous greater elements       // that are useless.       while     (     S  .  Count     !=     0     &&     arr  [  S  [  S  .  Count     -     1  ]]     >=     arr  [  i  ])         S  .  RemoveAt  (  S  .  Count     -     1  );     // Remove from rear       // Remove all previous smaller that are elements       // are useless.       while     (     G  .  Count     !=     0     &&     arr  [  G  [  G  .  Count     -     1  ]]      <=     arr  [  i  ])         G  .  RemoveAt  (  G  .  Count     -     1  );     // Remove from rear       // Add current element at rear of both deque       G  .  Add  (  i  );         S  .  Add  (  i  );         }         // Process rest of the Array elements       for     (     ;     i      <     arr  .  Length  ;     i  ++     )         {         // Element at the front of the deque 'G' & 'S'       // is the largest and smallest       // element of previous window respectively       sum     +=     arr  [  S  [  0  ]]     +     arr  [  G  [  0  ]];         // Remove all elements which are out of this       // window       while     (     S  .  Count     !=     0     &&     S  [  0  ]      <=     i     -     k  )         S  .  RemoveAt  (  0  );         while     (     G  .  Count     !=     0     &&     G  [  0  ]      <=     i     -     k  )         G  .  RemoveAt  (  0  );         // remove all previous greater element that are       // useless       while     (     S  .  Count     !=     0     &&     arr  [  S  [  S  .  Count  -  1  ]]     >=     arr  [  i  ])         S  .  RemoveAt  (  S  .  Count     -     1     );     // Remove from rear       // remove all previous smaller that are elements       // are useless       while     (     G  .  Count     !=     0     &&     arr  [  G  [  G  .  Count     -     1  ]]      <=     arr  [  i  ])         G  .  RemoveAt  (  G  .  Count     -     1  );     // Remove from rear       // Add current element at rear of both deque       G  .  Add  (  i  );         S  .  Add  (  i  );         }         // Sum of minimum and maximum element of last window       sum     +=     arr  [  S  [  0  ]]     +     arr  [  G  [  0  ]];         return     sum  ;         }         // Driver code      public     static     void     Main  (  String     []  args  )         {      int     []  arr     =     {  2       5       -  1       7       -  3       -  1       -  2  }     ;         int     k     =     4  ;         Console  .  WriteLine  (  SumOfKsubArray  (  arr       k  ));      }   }   // This code is contributed by gauravrajput1    
JavaScript
   // JavaScript program to find sum of all minimum and maximum   // elements Of Sub-array Size k.   // Returns sum of min and max element of all subarrays   // of size k   function     SumOfKsubArray  (  arr          k  )   {      let     sum     =     0  ;     // Initialize result      // The queue will store indexes of useful elements      // in every window      // In deque 'G' we maintain decreasing order of      // values from front to rear      // In deque 'S' we maintain increasing order of      // values from front to rear      let     S     =     [];      let     G     =     [];      // Process first window of size K      let     i     =     0  ;      for     (  i     =     0  ;     i      <     k  ;     i  ++  )      {      // Remove all previous greater elements      // that are useless.      while     (     S  .  length     !=     0     &&     arr  [  S  [  S  .  length     -     1  ]]     >=     arr  [  i  ])      S  .  pop  ();     // Remove from rear      // Remove all previous smaller that are elements      // are useless.      while     (     G  .  length     !=     0     &&     arr  [  G  [  G  .  length     -     1  ]]      <=     arr  [  i  ])      G  .  pop  ();     // Remove from rear      // Add current element at rear of both deque      G  .  push  (  i  );      S  .  push  (  i  );      }      // Process rest of the Array elements      for     (     ;     i      <     arr  .  length  ;     i  ++     )      {      // Element at the front of the deque 'G' & 'S'      // is the largest and smallest      // element of previous window respectively      sum     +=     arr  [  S  [  0  ]]     +     arr  [  G  [  0  ]];      // Remove all elements which are out of this      // window      while     (     S  .  length     !=     0     &&     S  [  0  ]      <=     i     -     k  )      S  .  shift  (  0  );      while     (     G  .  length     !=     0     &&     G  [  0  ]      <=     i     -     k  )      G  .  shift  (  0  );      // remove all previous greater element that are      // useless      while     (     S  .  length     !=     0     &&     arr  [  S  [  S  .  length  -  1  ]]     >=     arr  [  i  ])      S  .  pop  ();     // Remove from rear      // remove all previous smaller that are elements      // are useless      while     (     G  .  length     !=     0     &&     arr  [  G  [  G  .  length     -     1  ]]      <=     arr  [  i  ])      G  .  pop  ();     // Remove from rear      // Add current element at rear of both deque      G  .  push  (  i  );      S  .  push  (  i  );      }      // Sum of minimum and maximum element of last window      sum     +=     arr  [  S  [  0  ]]     +     arr  [  G  [  0  ]];      return     sum  ;   }   // Driver code      let     arr     =     [  2       5       -  1       7       -  3       -  1       -  2  ];      let     k     =     4  ;      console  .  log  (  SumOfKsubArray  (  arr       k  ));   // This code is contributed by _saurabh_jaiswal   

الإخراج
18 

تعقيد الوقت: O(n)
المساحة المساعدة: O(k)

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