PercolationStats.java

import edu.princeton.cs.algs4.StdIn;
import edu.princeton.cs.algs4.StdStats;
import edu.princeton.cs.algs4.StdRandom;
import edu.princeton.cs.algs4.WeightedQuickUnionUF;

public class PercolationStats {

    private double mean;
    private double stddev;
    private int arguments;
    private int[] totalOpenedSites;
    private double totalTrials;

    public PercolationStats(int n, int trials)    // perform trials independent experiments on an n-by-n grid
    {
        if (n < 0 || trials < 0) {
            throw new IllegalArgumentException();
        }
        int row;
        int col;
        arguments = n;
        totalTrials = trials;
        totalOpenedSites = new int[trials];
        for (int i = 0; i < trials; i++){
            int openSite = 0;
            Percolation percolation = new Percolation(n);
            while (percolation.percolates() != true){
                openSite = StdRandom.uniform(n*n);
                row = (openSite-(openSite%n))/n + 1;
                col = (openSite%n) + 1;
                if(!percolation.isOpen(row,col))
                    percolation.open(row, col);
        }
            totalOpenedSites[i] = percolation.numberOfOpenSites();
        }
        System.out.println("Mean                    = " + mean());
        System.out.println("stddev                  = " + stddev());
        System.out.println("95% confidence interval = [" + confidenceLo() + ", " + confidenceHi() + "]");
    }
    public double mean()                          // sample mean of percolation threshold
    {
        mean = StdStats.mean(totalOpenedSites);
        mean = mean/(arguments*arguments);
        return mean;
    }
    public double stddev()                        // sample standard deviation of percolation threshold
    {
        stddev = StdStats.stddev(totalOpenedSites);
        stddev = stddev / (arguments * arguments);
        return stddev;
    }
    public double confidenceLo()                  // low  endpoint of 95% confidence interval
    {
        return mean - (1.96*stddev)/Math.sqrt(totalTrials);
    }
    public double confidenceHi()                  // high endpoint of 95% confidence interval
    {
        return mean + (1.96*stddev)/Math.sqrt(totalTrials);
    }

    public static void main(String[] args)        // test client (described below)
    {
        int n = 10;
        int trials = 50000;
        PercolationStats perco = new PercolationStats(n, trials);
    }
}