优选帖子推荐算法测试

为了验证社区的优选帖子算法而写的测试类，实现了下 Comparable 接口，算是学习了。Reddit 这个算法是 D 大借鉴的，其中的道理完全看不懂，所谓的睁眼瞎就是这个样子了……

package org.b3log.symphony.util;
import org.testng.annotations.Test;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;

/**
 * Created by Zephyr on 2017/2/18. */
 public class redditScoreTest {
    @Test
  public void redditScore(){
        List votes=new ArrayList();
        Random random=new Random();
        for(int i=0;i<100;i++){
            int up=random.nextInt(100);
            int down=random.nextInt(100);
            double score=redditCommentScore(up,down);
            votes.add(new vote(i,up,down,score));
        }
        Collections.sort(votes);
        System.out.println(votes.toString());
    }
    private double redditCommentScore(final int ups, final int downs) {
        final int n = ups + downs;
        if (0 == n) {
            return 0;
        }
        final double z = 1.281551565545; // 1.0: 85%, 1.6: 95%, 1.281551565545: 80%
  final double p = (double) ups / n;

        return (p + z * z / (2 * n) - z * Math.sqrt((p * (1 - p) + z * z / (4 * n)) / n)) / (1 + z * z / n);
    }
}
class vote implements Comparable{
    int id;
    int up;
    int down;
    double score;
    public vote(){

    }
    public vote(int id,int up,int down,double score){
        this.id=id;
        this.up=up;
        this.down=down;
        this.score=score;
    }
    public int getUp() {
        return up;
    }
    public void setUp(int up) {
        this.up = up;
    }
    public int getDown() {
        return down;
    }
    public void setDown(int down) {
        this.down = down;
    }
    public double getScore() {
        return score;
    }
    public void setScore(double score) {
        this.score = score;
    }
    @Override
  public int compareTo(vote v) {
        if(this.score>v.score){
            return -1;
        }else if(this.scorescore){
            return 1;
        }else{
            return 0;
        }
    }
    @Override
  public String toString(){
        return this.id+" : "+this.up+" , "+this.down+" , "+this.score+"\n";
    }
}
​