leetcode-easy-dynamic-53 Maximum Subarray

mycode  66.85%

class Solution(object):
    def maxSubArray(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        res = resmax = 0
        flag = -1
        for i in range(len(nums)):
            if nums[i] < 0 :
                if res+nums[i] <= 0:                
                    res = 0
                else:                    
                    res += nums[i]
            if nums[i] > 0:
                flag = 1
                res += nums[i]
            resmax = max(resmax,res)
        if flag == -1:
            return max(nums)
        return resmax
             
        
        

参考

思路和上面是一样的，但是初始化不一样，所以不用单独去考虑列表中都为负数的情况

before用来记录短期的最大和，一旦自身变为了负数，就更新为当前值

res一直要去比较和before的大小，来更新为最大值

class Solution(object):
    def maxSubArray(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        res=before=nums[0]
        for num in nums[1:]:
            if before>=0:
                before=before+num
            else:
                before=num
            if res<before:
                res=before
        return res