Maximum Sub Array Sum

func maximumSubarraySum(arr []int) int {
    var maxSum, runningSum int
    for _, element := range arr {
        runningSum = max(runningSum, runningSum+element)
        maxSum = max(maxSum, runningSum)
    }
    return maxSum
}

func max(x, y int) int {
    if x > y {
        return x
    }
    return y
}