LintCode 138. Subarray Sum

题目

思路

trick。如果0−i$0-i$的和等于0−j$0-j$的和，那么i−j$i-j$的和为0。

代码

class Solution:
    """
    @param: nums: A list of integers
    @return: A list of integers includes the index of the first number and the index of the last number
    """
    def subarraySum(self, nums):
        # write your code here
        tmp_dict = {}
        tmp_dict[0] = -1
        sum = 0
        for i, v in enumerate(nums):
            sum += v
            if sum in tmp_dict:
                res_list = []
                res_list.append(tmp_dict[sum] + 1)
                res_list.append(i)
                return res_list
            tmp_dict[sum] = i