Python：如何求数组连续最大值

1.重复利用已经计算的子数组和：O(n²)

def maxSubArr(arr):
    if arr == None:
        print('数组为空')
        return
    maxsum = -2**31
    i = 0
    lens = len(arr)
    while i<lens :
        j = i
        sums = 0
        while j<lens :
            sums += arr[j]
            if sums > maxsum :
                maxsum = sums
            j += 1
        i += 1
    return maxsum

2.动态规划法：O(n)

def maxSubArr(arr):
    lens = len(arr)
    if arr == None or lens<1 :
        print('参数不合法')
        return
    ends = alls = arr[0]
    i = 1
    while i<lens :
        ends = max(ends+arr[i], arr[i]) #包含最后一个元素的最大子数组和
        alls = max(ends, alls)          #最大子数组和
        i += 1
    return alls