Two Sum

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LeetCode 问题页

Question

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

Example

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

Solution

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class Solution(object):
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        allindices = []
        for i in range(len(nums)):
            # The 'rest' is from 'target' minus each 'element' traversed from the list, and then judge whether the 'rest' is exist in list.
            rest = target - nums[i]
            if rest in nums:
                allindices.append((i, nums.index(rest)))
        indices = []
        for t in allindices:
            if t[0] != t[1]:
                indices.append(tuple(sorted(t)))
        return list(set(indices))
if __name__ == "__main__":
    s = Solution()
    indices = s.twoSum([0, 4, 3, 0], 0)
    print indices

Review

To improve the efficience of running, it’s need to optimize. And if you have a better idea or suggestion, please leave your words here!

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