Example 1:
Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Output: 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]
Implementation: TwoSum
Assuming there are no duplicate numbers, we can keep a map of number->index
. The if the complement exists at a different index, we have found our pair.
O(n)
O(n)