Two Sum

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

You can return the answer in any order.

 

Example 1:

Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].

Example 2:

Input: nums = [3,2,4], target = 6
Output: [1,2]

Example 3:

Input: nums = [3,3], target = 6
Output: [0,1]

 

Constraints:

• 2 <= nums.length <= 104
• -109 <= nums[i] <= 109
• -109 <= target <= 109
• Only one valid answer exists.

 

Follow-up: Can you come up with an algorithm that is less than O(n2)time complexity?

Related Topics

数组

哈希表

👍 19715

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解法

from typing import List


# leetcode submit region begin(Prohibit modification and deletion)
class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        restDic = {}
        for i, num in enumerate(nums):
            rest = target - num
            if rest in restDic:
                return [restDic[rest], i]
            restDic[num] = i

        return []

# leetcode submit region end(Prohibit modification and deletion)