Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Random;

public class Main {
    public static <T> ArrayList<T> rand(ArrayList<T> population, int nSamplesNeeded) {
        Random r = new Random();
        ArrayList<T> ret = new ArrayList<T>();

        if (nSamplesNeeded > population.size() / 2) {
            ArrayList<T> original = new ArrayList<T>();
            original = population;

            while (nSamplesNeeded > 0) {
                int rand = r.nextInt(original.size());
                if (rand < nSamplesNeeded) {
                    ret.add(original.get(rand));
                    original.remove(rand);
                    nSamplesNeeded--;
                }
            }
            original.clear();
        } else
            ret = shuffle(population, nSamplesNeeded);

        return ret;
    }

    public static <T> ArrayList<T> shuffle(ArrayList<T> population, int sample) {
        ArrayList<T> newList = new ArrayList<T>();
        ArrayList<T> ret = new ArrayList<T>();
        newList.addAll(population);

        Collections.shuffle(newList);
        ret.addAll(newList);
        for (int i = sample; i < ret.size(); i++) {
            ret.remove(i);
            i--;
        }
        newList.clear();
        return ret;
    }
}