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

public class CA {

    private int[][] A;
    private int[][] B; // is A after deaths
    private int[][] C; // is new births in A
    private int n;
    private double pointSize;
    private boolean trace;
    private Random gen;
    private double density; // between 0 and 1
    private double pBirth, pDeath;
    private int population;
    private int iteration;

    public CA(int n,double density,double pBirth,double pDeath){
	this.n = n;
	gen = new Random();
	pointSize = 0.1;
	this.density = density;
	this.pBirth = pBirth;
	this.pDeath = pDeath;
	population = 0;
	iteration = 0;
	A = new int [n][n];
	B = new int [n][n];
	C = new int [n][n];
	for (int i=0;i<n;i++)
	    for (int j=0;j<n;j++) 
		if (gen.nextDouble() <= density){
		    A[i][j] = 1;
		    population++;
		}
		else
		    A[i][j] = 0;
    }

    private boolean hasNeighbours(int[][] X,int x, int y){
	for (int i = Math.max(0,x-1);i<=Math.min(n-1,x+1);i++)
	    for (int j = Math.max(0,y-1);j<=Math.min(n-1,y+1);j++)
		if (X[i][j] == 1) return true;
	return false;
    }
	
		
    public void iterate(){
	// death
	for (int i=0;i<n;i++)
	    for (int j=0;j<n;j++)
		if (A[i][j] == 1 && gen.nextDouble() <= pDeath){
		    B[i][j] = 0;
		    population--;
		}
		else 
		    B[i][j] = A[i][j];
	// birth
	for (int i=0;i<n;i++)
	    for (int j=0;j<n;j++)
		if (A[i][j] == 0 && hasNeighbours(A,i,j) && gen.nextDouble() <= pBirth){
		    C[i][j] = 1;
		    population++;
		}
		else
		    C[i][j] = 0;
	// Copy over B or C into A
	for (int i=0;i<n;i++)
	    for (int j=0;j<n;j++)
		A[i][j] = Math.max(B[i][j],C[i][j]);
	iteration++;
    }		

    public void plot() {
	StdDraw.clear(StdDraw.LIGHT_GRAY);
	StdDraw.setXscale(-2,n);
        StdDraw.setYscale(-2,n);
        StdDraw.show(0);	
	for (int i=0;i<n;i++)
	    for (int j=0;j<n;j++)
		if (A[i][j] != 0) StdDraw.circle(i,j,pointSize);
	StdDraw.textLeft(-2,-2,stats());
        StdDraw.show(0);
    }

    public boolean trace(){trace = !trace; return trace;}
    public boolean getTrace(){return trace;}
    public void setPointSize(double x){pointSize = x;}
    public void setDensity(double p){density = p;}
    public void setBirth(double p){pBirth = p;}
    public void setDeath(double p){pDeath = p;}
    public int size(){return n;}

    public void pause(long l){
	try{Thread.sleep(l);}
	catch (Exception e) {e.printStackTrace();}
    }

    public String stats(){
	String s = "n: " + n +"X"+ n + " birth: " + pBirth + " death: " + pDeath + " pop: " + population;
	s = s + " iteration: " + iteration;
	return s;
    }
}