连续子数组的最大和

方法一：遍历数组，遇到负和则抛弃之前的结果，重新积累，期间保留最大值

# -*- coding:utf-8 -*-
class Solution:
    def FindGreatestSumOfSubArray(self, array):
        # write code here
        if not array:
            return
        max=array[0]
        tmp=array[0]
        for i in range(1,len(array)):
            if tmp<0:
                tmp=array[i]
            else:
                tmp+=array[i]
            if tmp>max:
                max=tmp
        return max

方法二：动态规划

dp[i]表示i个数的最大和，计算dp[i]

if dp[i - 1] <= 0:
    dp.append(num)
else:
    dp.append(dp[i - 1] + num)

class Solution:
    def FindGreatestSumOfSubArray(self,array):
        if not array:
            return 0

        dp = [array[0]]

        i = 1
        for num in array[1:]:
            if dp[i - 1] <= 0:
                dp.append(num)
            else:
                dp.append(dp[i - 1] + num)
            i += 1
        return max(dp)