circuMaxSumSubArray.c++

// maximum Circular SubArray sum problem

#include<iostream>
#include<climits>
using namespace std;

int kadane(int arr[], int n){
	int currSum = 0;
	int maxSum = INT_MIN;
	for(int i=0; i<n; i++){
		currSum += arr[i];
		if(currSum<0)
			currSum = 0;
		maxSum = max(maxSum, currSum);
	}
	return maxSum;
}

int main()
{
	int n;
	cin>>n;
	
	int arr[n];
	for(int i=0; i<n; i++){
		cin>>arr[i];
	}
	
	int wrapsum= 0;
	int nonwrapsum = 0;
	
	nonwrapsum = kadane(arr, n);
	
	int totalSum = 0;
	for(int i=0; i<n; i++){
		totalSum += arr[i];
		arr[i] = -arr[i];
	}
	
	wrapsum = totalSum-(-kadane(arr, n));
	
	cout<<max(wrapsum, nonwrapsum)<<endl;
	return 0;
}