找水王

思路：水王的发帖数超过了总帖数的一半，水王的帖子要比其他所有人的帖子加起来还要多。比较相邻两个发帖ID，若不相同，把两个帖子全部删除；若相删除一个，在这之后再继续比较。到最后剩下的就是水王的id。

package test2;

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.IOException;

public class ShuiWang {

    public static void main(String[] args) throws IOException {

        find();

    }

    public static void find() throws IOException {

        BufferedReader br = new BufferedReader(new FileReader("sw.txt"));

        String s,s1 = null,s2 = null,shuiwang = null;

        int i=1;

        while((s = br.readLine()) != null) {

            s1 = s;

            if(s2 == null) {

                s2 = br.readLine();

            }

            System.out.println("------------------------------------------");

            System.out.println("第" + i++ + "次比较");

            System.out.println("s1:" + s1);

            System.out.println("s2:" + s2);

            if(s2 != null) { 

                if(s1.compareTo(s2) != 0) 

                    s2 = null;

                else                      

                    shuiwang = s2;

            }else {

                shuiwang = s1;

            }

            System.out.println("记录id:" + shuiwang);

        }

        if(shuiwang == null)

            shuiwang = s2;

        System.out.println("
水王id为:" + shuiwang);

        br.close();

    }

}