leetcode——560. 和爲K的子數組

class Solution(object):
    def subarraySum(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: int
        """

        res = 0
        asum = 0
        map = dict()

        map[0]=1

        for n in nums:
            asum+=n
            if asum-k in map:
                res+=map[asum-k]
            if asum in map:
                map[asum]+=1
            else:
                map[asum]=1

        return res