two sum

#array, #easy, link to problem ↗

thinking

we just cannot sort in this because we have to preserve the index, so instead we use hashmap.

solution

def twoSum(self, nums: List[int], target: int) -> List[int]:
    hashmap = {}
    for i in range (0, len(nums)):
        val = target - nums[i]

        if nums[i] in hashmap:
            return [hashmap[nums[i]], i]

        hashmap[val] = i