Maximum circular sum via array ? not getting how to do

#1

You are provided n numbers (both +ve and -ve). Numbers are arranged in a circular form. You need to find the maximum sum of consecutive numbers.

Input Format
First line contains integer t which is number of test case.
For each test case, it contains an integer n which is the size of array and next line contains n space separated integers denoting the elements of the array.

Constraints
1<=t<=100
1<=n<=1000
|Ai| <= 10000

Output Format
Print the maximum circular sum for each testcase in a new line.

Sample Input
1
7
8 -8 9 -9 10 -11 12
Sample Output
22
Explanation
Maximum Circular Sum = 22 (12 + 8 - 8 + 9 - 9 + 10)

#2

approach is using kadan’s algorithm for circular subarray

There can be two cases for the maximum sum:

Case 1: The elements that contribute to the maximum sum are arranged such that no wrapping is there. Examples: {-10, 2, -1, 5}, {-2, 4, -1, 4, -1}. In this case, Kadane’s algorithm will produce the result.

Case 2: The elements which contribute to the maximum sum are arranged such that wrapping is there. Examples: {10, -12, 11}, {12, -5, 4, -8, 11}. In this case, we change wrapping to non-wrapping.find out the sum of non contributing elements and subtract this sum from the total sum. To find out the sum of non contributing, invert sign of each element and then run Kadane’s algorithm.

now take max of these two case
Code:

#3

why this process we r doing ??

like inverting and then kadane’s ???//
not getting the reason behind it

#4

kadane’s algo usually returns the maximum subarray sum but if we invert the array it would return minimum subarray sum

#5

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