Ej 2 SocialDistance.java

public class SocialDistance {
    /**
     * 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 rodeado = 0;
        if (layout==null){
            throw new IllegalArgumentException("Disposición nula\n");
        }

        int rowLength = layout[0].length;
        for (char[] fila : layout) {
            if (fila.length != rowLength) {
                throw new IllegalArgumentException("Ragged array\n");
            }
        }

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


        for(i=0,j=0; layout[i][j] != 0; i++){
            for(j=0; layout[i][j] != 0; j++){
                if(layout[i][j] == 'A'){
                    layout[i][j] = '#';
                }
            }
        }

        for(i=0,j=0; layout[i][j] != 0; i++){
            for(j=0; layout[i][j] != 0; j++){
                if(layout[i][j] == '#'){
                    if(layout[i][j-1]== '#'){
                        rodeado++;
                    }
                    if(layout[i][j+1]== '#'){
                        rodeado++;
                    }
                    if(layout[i-1][j]== '#'){
                        rodeado++;
                    }
                    if(layout[i-1][j-1]== '#'){
                        rodeado++;
                    }
                    if(layout[i-1][j+1]== '#'){
                        rodeado++;
                    }
                    if(layout[i+1][j]== '#'){
                        rodeado++;
                    }
                    if(layout[i+1][j-1]== '#'){
                        rodeado++;
                    }
                    if(layout[i+1][j+1]== '#'){
                        rodeado++;
                    }
                    if(rodeado>=4){
                        layout[i][j] = 'A';
                    }
                }
            }
        }

        for(i=0,j=0; layout[i][j] != 0; i++){
            for(j=0; layout[i][j] != 0; j++){
                if(layout[i][j] == 'A'){
                    if(layout[i][j-1]== '#'){
                        rodeado++;
                    }
                    if(layout[i][j+1]== '#'){
                        rodeado++;
                    }
                    if(layout[i-1][j]== '#'){
                        rodeado++;
                    }
                    if(layout[i-1][j-1]== '#'){
                        rodeado++;
                    }
                    if(layout[i-1][j+1]== '#'){
                        rodeado++;
                    }
                    if(layout[i+1][j]== '#'){
                        rodeado++;
                    }
                    if(layout[i+1][j-1]== '#'){
                        rodeado++;
                    }
                    if(layout[i+1][j+1]== '#'){
                        rodeado++;
                    }
                    if(rodeado<4){
                        layout[i][j] = '#';
                    }
                }
            }
        }


    return layout;
    }
}