(SPOJ) Costa - Solution

Link to the problem: http://br.spoj.com/problems/COSTA12/

For every position that is corresponding to ground, the solution below checks if this position is surrounded by water or nothing.


import java.io.*;
import java.util.*;

class Main {
    public char[][] matrix;
    public int[] vi = {-1,0,0,1};
    public int[] vj = {0,-1,1,0};
   
    public void process() throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
       
        String line = br.readLine();
        String[] s = line.split(" ");
        int numRows = Integer.parseInt(s[0]);
        int numCols = Integer.parseInt(s[1]);
        matrix = new char[numRows][numCols];
        for (int i = 0; i < numRows; i++) {
            line = br.readLine();
            for (int j = 0; j < numCols; j++) {
                matrix[i][j] = line.charAt(j);
            }
        }
       
        int countCoast = 0;
        for (int i = 0; i < numRows; i++) {
            for (int j = 0; j < numCols; j++) {
                if (matrix[i][j] == '#') {
                    for (int k = 0; k < 4; k++) {
                        int nextI = i+vi[k];
                        int nextJ = j+vj[k];
                        if ((nextI < 0 || nextJ < 0 || nextI >= numRows || nextJ >= numCols) ||
                            (nextI >= 0 && nextJ >= 0 && nextI < numRows && nextJ < numCols && matrix[nextI][nextJ] == '.')) {
                            countCoast++;
                            break;
                        }
                    }
                }
            }
        }
       
        bw.write(countCoast+"\n");
           
        bw.flush();
        bw.close();
       
        return;
    }
   
    public static void main(String[] args) throws NumberFormatException, IOException {
        Main m = new Main();
        m.process();
       
        System.exit(0);
    }
}