找水王

要求：

　　UNIN队设计了一个灌水论坛。信息学院的学生都喜欢在上面交流灌水，传说在论坛上有一个“水王”，他不但喜欢发帖，还会回复其他ID发的每个帖子。坊间风闻该“水王”发帖数目超过了帖子数目的一半。

　　如果你有一张当前论坛的帖子（包括回帖）列表，其中帖子的作者的ID也在其中，你能快速的找到这个传说中的水王吗？

设计思路：

　　发帖者的id随机生成动态数组。水王发帖数量最多，最不怕消除，利用这点，消除相邻元素id不同的两个元素，最后剩下的就是“水王”。

实现代码：

//找水王（在一个论坛中，发帖数超过总帖数的一半的那个id号）
#include<iostream>
#include<string>
#define N 10     //可以定义列表长度

using namespace std;
int main()
{
    string king;
    //定义列表
    string IdList[N]={"2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员"};
    //string IdList[N]={"2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员","2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员"};
    //string IdList[N]={"2水货","2水货","3潜水员","2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员","2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员"};
    //string IdList[N]={"oottt","eee","ott","oottt","oottt","oottt","oottt","oottt","tt55","oottt"};
    //string IdList[N]={"1","2","3","1","1","1","1","2","5","1"};
    //假设第一个id是水王
    int i=0;
    int num=1;
    king=IdList[0];
    for(i=1;i<N;i++)
    {
        //如果当前id和king id不同
        if(IdList[i]!=king)
        {
            //num-1
            num=num-1;
            //num为0，将下一个id 设为 king，并直接跳过下一次循环,并将 num设为1
            //若num不为0，king 不变
            if(num==0)
            {
                king=IdList[i+1];
                i=i+1;
                num=1;
            }
        }
        //若id和king id相同，num+1
        else
        {
            king=IdList[i];
            num=num+1;
        }
    }
    cout<<"要找的水王的 id 为:"<<king<<endl;
    return 0;
}

运行结果：

①测试文字列表string IdList[10]={"2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员"};

　　②测试更长的列表string IdList[30]={"2水货","2水货","3潜水员","2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员","2水货","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","3潜水员","1水王","3潜水员","1水王","1水王","1水王","1水王","2水货","3潜水员"};

　　③测试数字和普通字符串

string IdList[10]={"oottt","eee","ott","oottt","oottt","oottt","oottt","oottt","tt55","oottt"};

string IdList[10]={"1","2","3","1","1","1","1","2","5","1"};

 6、总结分析：

　　　这次的问题比较简单，实现起来不是很难，但方法的好坏决定了这个程序的运算时间和复杂度。