// Package q918 implements a solution for https://leetcode.com/problems/maximum-sum-circular-subarray/
package q918

func maxSubarraySumCircular(nums []int) int {
	maxSum, minSum, maxPfx, minPfx := nums[0], nums[0], 0, 0

	sum := 0
	for _, num := range nums {
		sum += num
		maxSum = max(maxSum, sum-minPfx)
		minSum = min(minSum, sum-maxPfx)

		maxPfx = max(maxPfx, sum)
		minPfx = min(minPfx, sum)
	}

	if sum == minSum {
		return maxSum
	}
	return max(maxSum, sum-minSum)
}

var _ = maxSubarraySumCircular