✅Alternate Matrix Addition(Contest)

Alternate Matrix Addition medium Time Limit: 2 sec Memory Limit: 128000 kB

Problem Statement :

You are given a chessboard of size N x N, where the top left square is black. Each square contains a value. Find the sum of the values of all black squares and all white squares.

Remember that in a chessboard black and white squares are alternate. Input The first line of input will be the N size of the matrix. Then next N lines will consist of elements of the matrix. Each row will contain N elements since it is a square matrix.

Constraints:- 1 ≤ N ≤ 800 1 ≤ Matrix[i][j] ≤ 100000 Output Print two lines, the first line containing the sum of black squares and the second line containing the sum of white squares.

Example

Input 1: 3 1 2 3 4 5 6 7 8 9

Output 1: 25 20

Sample Input 2: 4 1 2 3 4 6 8 9 10 11 12 13 14 15 16 17 18

Sample Output 2: 80 79

Explanation 1 The black square contains 1, 3, 5, 7, 9; sum = 25 The white square contains 2, 4, 6, 8; sum = 20

link: https://my.newtonschool.co/playground/code/e0qrt52bv7e1/

import java.io.*; // for handling input/output
import java.util.*; // contains Collections framework

// don't change the name of this class
// you can add inner classes if needed
class Main {
    public static void main (String[] args)throws IOException {
        // Your code here
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        int arr[][] = new int[n][n];
        for(int i=0;i<n;i++){
            String []input = br.readLine().split(" ");
            for(int j=0;j<n;j++){
                arr[i][j] = Integer.parseInt(input[j]);
            }
        }
        matSum(arr,n);

    }
    static void matSum(int arr[][], int n){
        long sum = 0,sum1 = 0;
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                if((i+j)%2==0){
                    sum += arr[i][j];
                    
                }else{
                    sum1 += arr[i][j];
                }
            }
        }
        System.out.println(sum);
        System.out.println(sum1);
    }
}
 
 //method 02
 ```java
import java.io.*; // for handling input/output
import java.util.*; // contains Collections framework

// don't change the name of this class
// you can add inner classes if needed
class Main {
    public static void main (String[] args) {
        // Your code here
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int arr[][] = new int [n][n];
        for(int i=0; i<n; i++){
            for(int j=0; j<n; j++){
                arr[i][j] = in.nextInt();
            }
        }
        int blackSum = 0;
        int whiteSum = 0;
        for(int i=0; i<n; i++){
            for(int j=0; j<n; j++){
                if((i+j)%2 ==0){
                    blackSum += arr[i][j];
                }else{
                    whiteSum += arr[i][j];
                }
            }
        }
        System.out.println(blackSum);
        System.out.println(whiteSum);
    }
}
```