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Solving Two Sum in Python

The challenge

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.


Given nums = [2, 7, 11, 15], target = 9,

Because nums[] + nums[1] = 2 + 7 = 9,
return [, 1].

The solution in Python

class Solution: def twoSum(self, nums: List[int], target: int) -> List[int]: # keep a hashmap of items found seen = {} # loop through the nums, with int and value for i, v in enumerate(nums): # set remaining to the target minus the value remaining = target - v # check if the new value is in the hashmap if remaining in seen: # return it and the index return [seen[remaining], i] # otherwise, put it on the map instead seen[v] = i # nothing found, return an empty list return []
Code language: Python (python)

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