https://school.programmers.co.kr/learn/courses/30/lessons/12950
class Solution {
public int[][] solution(int[][] arr1, int[][] arr2) {
int[][] answer = new int[arr1.length][arr1[0].length];
for(int i = 0; i < arr1.length; i++){
for(int j = 0; j < arr1[0].length; j++){
answer[i][j] = arr1[i][j] + arr2[i][j];
}
}
return answer;
}
}