Bit Shift Matrix

package com.company;

import java.math.BigInteger;
import java.util.Arrays;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int r = in.nextInt();
        int c = in.nextInt();
        int n = in.nextInt();
        in.nextLine();

        String movements = in.nextLine();
        String[] code = movements.split(" ");
        double[] codes = Arrays.stream(code).mapToDouble(Double::parseDouble).toArray();

        int coeff = Math.max(r, c);

        BigInteger[][] matrix = new BigInteger[r][c];

        BigInteger counter = BigInteger.valueOf(1);
        for (int row = r - 1; row >= 0; row--) {
            for (int col = 0; col < c; col++) {
                matrix[row][col] = counter;
                if (col < c - 1) {
                    counter = counter.multiply(BigInteger.valueOf(2));
                }
            }
            counter = matrix[row][1];
        }

//        check matrix
//        for (int row = 0; row < r; row++) {
//            for (int col = 0; col < c; col++) {
//                System.out.print(matrix[row][col] + " ");
//            }
//            System.out.println();
//        }

        int currentRow = r - 1;
        int currentCol = 0;
        BigInteger sum = matrix[currentRow][currentCol];
        matrix[currentRow][currentCol] = BigInteger.valueOf(0);

        for (int i = 0; i < codes.length; i++) {
            int targetRow = (int)codes[i] / coeff;
            int targetCol = (int)codes[i] % coeff;
            while (targetCol != currentCol) {
                if (targetCol > currentCol) {
                    currentCol++;
                } else {
                    currentCol--;
                }
                sum = sum.add(matrix[currentRow][currentCol]);
                matrix[currentRow][currentCol] = BigInteger.valueOf(0);
            }
            while (targetRow != currentRow) {
                if (targetRow > currentRow) {
                    currentRow++;
                } else {
                    currentRow--;
                }
                sum = sum.add(matrix[currentRow][currentCol]);
                matrix[currentRow][currentCol] = BigInteger.valueOf(0);
            }
        }
        System.out.println(sum);
    }
}