[Java/LeetCode]1.Two Sum

- 문제설명

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.

[제한사항]

2 <= nums.length <= 103
-10^9 <= nums[i] <= 10^9
-10^9 <= target <= 10^9
Only one valid answer exists.

입출력 예

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]

— 영어로 된 코딩문제는 처음풀어보는거라 쉬운문제를 선택했다.
무식하게 for문으로 찾아보는 방법으로 풀었는데 생각보다 느리진 않았다.

Runtime: 10 ms, faster than 38.11% of Java online submissions for Two Sum.
Memory Usage: 39.5 MB, less than 28.18% of Java online submissions for Two Sum.

class Solution {
    public int[] twoSum(int[] nums, int target) {
        
        int[] answer = new int[2];
        
        for(int i=0; i<nums.length-1; i++){
            for(int j=i+1; j<nums.length; j++){
                if(nums[i]+nums[j]==target){
                    answer[0] = i;
                    answer[1] = j;
                }
            }
        }
        
        return answer;
    }
}

— 다른사람 풀이 참고 https://limdongjin.github.io/problemsolving/twosum.html#list%EC%9D%98-lastindexof-%EB%A9%94%EC%86%8C%EB%93%9C%EB%A1%9C-%ED%92%80%EC%96%B4%EB%B3%B4%EA%B8%B0-125ms