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Reverse Spiral Form of Matrix
Medium Accuracy: 75.6% Submissions: 485 Points: 4

Given a matrix as 2D array. Return the matrix in reverse spiral form.​

Example 1:

Input: R = 3, C = 3
  a = {{9, 8, 7},
       {6, 5, 4},
       {3, 2, 1}}
Output: {5 6 3 2 1 4 7 8 9} 
Explanation: Spiral form of the matrix
is 9->8->7->4->1->2->3->6->5 and then 
reverse.


Example 2:

Input: R = 4, C = 4 
  a = {{1, 2, 3, 4},
       {5, 6, 7, 8},
       {9, 10, 11, 12}, 
       {13, 14, 15, 16}}
Output: {10 11 7 6 5 9 13 14 15 16 12 8 4 3 2 1}
Explanation: Spiral form of the matrix
is 1->2->3->4->8->12->16->15->14->13->9
->5->6->7->11->10 and then reverse. 


Your Task:  
You dont need to read input or print anything. Complete the function reverseSpiral() which takes R, C and a as input parameters and returns the matrix in reverse spiral form.


Expected Time Complexity: O(R*C)
Expected Auxiliary Space: O(R*C)

Constraints:
1 <= R,C <=100
1 <= a[R][C] <=100

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Reverse Spiral Form of Matrix

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