Hackerrank – Problem description
The problem description – Hackerrank.
Solution
We have to calculate products of number foursomes for all directions in a grid and take the greatest product value.
I created solution in:
All solutions are also available on my GitHub profile.
Java
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import java.util.Scanner; public class LargestProductGrid { private static final int N = 20; private static final int ADJACENT = 4; public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int[][] visited = new int[N][N]; int[][] matrix = new int[N][N]; for (int i = 0; i < N; i++) { for (int j = 0; j < N; j++) { matrix[i][j] = scanner.nextInt(); } } System.out.println(max(matrix, visited)); scanner.close(); } private static long max(int[][] matrix, int[][] visited) { long max = 0; for (int i = 0; i < N; i++) { for (int j = 0; j < N; j++) { long product = productToRight(matrix, i, j); if (product > max) { max = product; } product = productToDown(matrix, i, j); if (product > max) { max = product; } product = productToDiagRight(matrix, i, j); if (product > max) { max = product; } product = productToDiagLeft(matrix, i, j); if (product > max) { max = product; } } } return max; } private static long productToRight(int[][] matrix, int i, int j) { long product = 1; if (j <= N - ADJACENT) { for (int r = j; r < j + ADJACENT; r++) { product *= matrix[i][r]; } } return product; } private static long productToDown(int[][] matrix, int i, int j) { long product = 1; if (i <= N - ADJACENT) { for (int r = i; r < i + ADJACENT; r++) { product *= matrix[r][j]; } } return product; } private static long productToDiagRight(int[][] matrix, int i, int j) { long product = 1; int s = j; if (i <= N - ADJACENT && j <= N - ADJACENT) { for (int r = i; r < i + ADJACENT; r++) { product *= matrix[r][s++]; } } return product; } private static long productToDiagLeft(int[][] matrix, int i, int j) { long product = 1; if (i <= N - ADJACENT && j >= ADJACENT - 1) { for (int r = i; r < i + ADJACENT; r++) { product *= matrix[r][j--]; } } return product; } } |