leetcode 1. 两数之和

发表于 分类于 阅读次数：

遍历数组即可

时间复杂度：O(n)
空间复杂度：O(n)

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class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        num_to_index = dict([(num, i) for i, num in enumerate(nums)])
        for i, num in enumerate(nums):
            expected_num_index = num_to_index.get(target-num)
            if expected_num_index and expected_num_index > i:
                return [i, expected_num_index]
        return []