Given an array of integers, return indices of the two numbers such that they add up to a specific target.
You may assume that each input would have exactly one solution, and you may not use the same element twice.

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Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

思路

因为题目给出的数组当中一定会有且只有一个解，而且不能重复用一个元素。所以第一层循环用以遍历数组中的元素，第二层循环用以查询此元素之后，是否还有元素满足要求。

因为这一题的难度是easy，所以利用上面所说，类似于穷举的方法就可以直接得到结果，不需要考虑额外的时间复杂度。

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class Solution(object):
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        length = len(nums)
        for i in range(length):
            remain = target - nums[i]
            for j in range(i+1, length):
                if (nums[j] == remain):
                    return [i, j]