Find the indices of two numbers that add up to the target value in a list of...

Problem

Given a list of integers and a target value, write a function that returns the indices of the two numbers that add up to the target.
Example input: [2, 7, 11, 15], target=9
Example output: [0, 1]

Solution

This solution is in Python. Our A.I. can create solutions in multiple languages.

kayakane

def two_sum(nums, target):
    """
    :type nums: List[int]
    :type target: int
    :rtype: List[int]
    """
    # create a dictionary to store the difference between the target and the current number
    # as the key and the index of the current number as the value
    # if the current number is in the dictionary, return the index of the current number and the value of the key
    # otherwise, add the difference between the target and the current number as the key and the index of the current number as the value
    d = {}
    for i in range(len(nums)):
        if nums[i] in d:
            return [d[nums[i]], i]
        else:
            d[target - nums[i]] = i