1. Two Sum

1. Two Sum 

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

You can return the answer in any order.

 

Example 1

Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Explanation: 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]

 

Constraints:

• 2 <= nums.length <= 104
• -10^9 <= nums[i] <= 10^9
• -10^9 <= target <= 0^9
• Only one valid answer exists.

Code

class Solution {
    func twoSum(_ nums: [Int], _ target: Int) -> [Int] {
        var numMap = [Int:Int]()
        for(index, num) in nums.enumerated() {
            let complement = target - num
            if let complementIndex = numMap[complement] {
                return [complementIndex, index]
            }
            numMap[num] = index
        }
        return []
    }
}

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공부하는 공돌이, 공공돌입니다🐻

@sheep1sik