Talk is cheap.

func maxSubArray(nums []int) int {
    tmp := nums[0]
    best := nums[0]
    for _, v := range nums[1:] {
        tmp = max(v, v + tmp)
        best = max(best, tmp)
    }
    return best
}

func max(a, b int) int {
    if a > b {
        return a
    }
    return b
}