Leetcode - 1. Two Sum (哈希表)

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.

Example:

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

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

 

def twoSum(nums,target):
    seen = {}
    
    for i,n in enumerate(nums):
        if target-n in seen:
            return [i,seen[target-n]]

        else:
            seen[n] = i