EJ 2 DS FINAL

package SocialDistance;

public class SocialDistance {
    public static int[][] crearMatrizRodeados(char[][] layout){
        int i;
        int j;
        int rodeados[][] = new int[layout.length][layout[0].length];
        for(i = 0; i< layout.length; i++){
            for(j= 0; j<layout[0].length; j++){
                rodeados[i][j]=0;
            }
        }
        return rodeados;
    }


    public static int[][] contarRodeados(char[][] layout){
        int i;
        int j;
        int [][] rodeados;
        rodeados= crearMatrizRodeados(layout);
        for(i=0; i<layout.length; i++){
            for(j=0; j<layout[i].length; j++){

                if( j>0 && layout[i][j-1]== '#'){
                    rodeados[i][j]++;
                }
                if(j<layout[i].length-1  && layout[i][j+1]== '#'){
                    rodeados[i][j]++;
                }
                if(i>0) {
                    if (j > 0 && layout[i - 1][j - 1] == '#') {
                        rodeados[i][j]++;
                    }
                    if (layout[i - 1][j] == '#') {
                        rodeados[i][j]++;
                    }
                    if (j < layout[i].length - 1 && layout[i - 1][j + 1] == '#') {
                        rodeados[i][j]++;
                    }
                }
                if(i< layout.length-1) {

                    if (j > 0 && layout[i +1][j - 1] == '#') {
                        rodeados[i][j]++;
                    }
                    if (layout[i + 1][j] == '#') {
                        rodeados[i][j]++;
                    }
                    if (j < layout[i].length - 1 && layout[i + 1][j + 1] == '#') {
                        rodeados[i][j]++;
                    }
                }
            }
        }
        return rodeados;
    }





    /**
     * Given the layout of a class with available seats marked with an ’A’ and
     * invalid sites marked with a ’. ’, returns the resulting layout with the
     * sites occupied by the students marked with a ’#’ following two rules :
     * - Students occupy an empty seat if there are no other adjacent students .
     * - A student leaves a seat empty if he/ she has 4 or more adjacent students .
     * @param layout The initial layout .
     * @return The resulting layout .
     * @throws IllegalArgumentException if the initial layout is invalid (is null ,
     * is ragged , includes characters other than ’.’ or ’A ’)).
     */
    public static char [][] seatingPeople ( char [][] layout ) {
        int i;
        int j;
        int rodeados[][];
        boolean cambio;


        if (layout == null) {
            throw new IllegalArgumentException("Disposición nula\n");
        }

        int rowLength0 = layout[0].length;
        for (j = 1; j < layout.length; j++) {
            if (layout[j].length != rowLength0) {
                throw new IllegalArgumentException("Ragged array\n");
            }
        }

        for (i = 0; i < layout.length; i++) {
            for (j = 0; j < layout[i].length; j++) {
                if (layout[i][j] != 'A' && layout[i][j] != '.') {
                    throw new IllegalArgumentException("Caracteres invalidos\n");
                }
            }
        }

        do {
            cambio = false;
            rodeados = contarRodeados(layout);


            for (i = 0; i < layout.length; i++) {
                for (j = 0; j < layout[i].length; j++) {
                    if (layout[i][j] == 'A' && rodeados[i][j] == 0) {
                        layout[i][j] = '#';
                        cambio = true;
                    }
                }
            }

            rodeados = contarRodeados(layout);

            for (i = 0; i < layout.length; i++) {
                for (j = 0; j < layout[i].length; j++) {
                    if (layout[i][j] == '#' && rodeados[i][j] >= 4) {
                        layout[i][j] = 'A';
                        cambio = true;
                    }
                }
            }
        }while(cambio==true);


        return layout;
    }
}