[hackerrank] Diagonal Difference

 

 

배열의 우대각선, 좌대각선의 값을 더한 후, 우대각선 - 좌대각선 값의 절대값을 구한다.

특이한 점은 중첩 List를 써서, get value 시 get(i).get(j) 하면 배열과 같이 값을 가져올 수 있다.

Java 의 절대값은 Math.abs() 하면 된다.

 

 

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'diagonalDifference' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts 2D_INTEGER_ARRAY arr as parameter.
     */

    public static int diagonalDifference(List<List<Integer>> arr) {
    // Write your code here
       int startnum = 0;
       int endnum =  arr.size();
       int chknum = arr.size()-1;
       int selectnum1 = 0;
       int selectnum2 = 0;

       int[][] insnum = new int[endnum][endnum];

       for(int i=0;i<endnum;i++){


            System.out.println(arr.get(i)); 
               for(int j=0;j<endnum;j++){

                       
                   if(i+j==chknum){
                          selectnum1 = selectnum1 + arr.get(i).get(j);
                   }

                   if(i-j==0){
                         selectnum2 = selectnum2 + arr.get(i).get(j);
                   }



                    //[0][0],[0][1],[0][2],[0][3]
                    //[1][0],[1][1],[1][2],[1][3]
                    //[2][0],[2][1],[2][2],[1][3]
                    //[3][0],[3][1],[3][2],[3][3]

               }

               System.out.println (selectnum1);
               System.out.println (selectnum2);

       }

       return Math.abs(selectnum1 - selectnum2);
      

    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = Integer.parseInt(bufferedReader.readLine().trim());

        List<List<Integer>> arr = new ArrayList<>();

        IntStream.range(0, n).forEach(i -> {
            try {
                arr.add(
                    Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
                        .map(Integer::parseInt)
                        .collect(toList())
                );
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            }
        });

        int result = Result.diagonalDifference(arr);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}