剔除list中相同的结构体数据

剔除list中相同的结构体数据，有三个思路：
1、两层循环，逐个比较

2、使用set容器来剔除

3、使用unique方法去重

// deduplication.cpp : 定义控制台应用程序的入口点。
//
#include <list>
#include <set>
#include <iostream>
#include <algorithm>
#include <vector>
#include <tchar.h>
using namespace std;

struct tagRecentGameItem
{
    std::wstring strGameCode;
    std::wstring strServerID;
    __int64 nTime;
    tagRecentGameItem()
        : strGameCode(L"")
        , strServerID(L"")
        , nTime(0)
    {
    }

    bool operator < (const tagRecentGameItem& right) const
    {
        if (this->nTime > right.nTime)
        {
            return true;
        }
        if (this->nTime == right.nTime)
        {
            //compare函数在>时返回1，<时返回-1，==时返回0
            return this->strGameCode.compare(right.strGameCode) < 0;
        }
        return false;
    }
    bool operator == (const tagRecentGameItem& right) const
    {
        bool bEqual = false;
        //_tcsicmp不区分大小写，wcscmp区分大小写
        bEqual = ( 0 == _tcsicmp(this->strGameCode.c_str(), right.strGameCode.c_str()) );
        bEqual &= ( 0 == _tcsicmp(this->strServerID.c_str(), right.strServerID.c_str()) );
        return bEqual;
    }
};
//
typedef std::list<tagRecentGameItem> listRecentGame;
typedef std::set<tagRecentGameItem> setRecentGame;
//
listRecentGame m_LocalList;
listRecentGame m_RemoteList;
setRecentGame m_setGames;

//打印结果
void print_result(listRecentGame& items)
{
    listRecentGame::iterator iter = items.begin();
    for (iter; iter!=items.end(); ++iter)
    {
        printf("gameCode: %ls
", iter->strGameCode.c_str());
    }
    printf("
");
}
//逐个比较
void deduplication1(listRecentGame& items)
{
    printf("method :deduplication1
");

    items.sort();//需要重载操作符<
    listRecentGame::iterator itrB = items.begin();
    listRecentGame::iterator itrE = items.end();
    listRecentGame::iterator itr;
    for (itrB; itrB != itrE; ++itrB)
    {
        itr = itrB;
        ++itr;
        for(itr; itr != itrE;)
        {
            if (*itr == *itrB)
            {
                items.erase(itr++);
            }
            else
            {
                ++itr;
            }
        }
    }

    //打印结果
    print_result(items);
}
//利用set容器特性去重
void deduplication2(listRecentGame& items)
{
    printf("method :deduplication2
");

    listRecentGame::iterator iter1 = items.begin();
    listRecentGame::iterator iter2 = items.end();
    for (iter1; iter1 != iter2; ++iter1)
    {
        //需要重载操作符<
        m_setGames.insert(*iter1);
    }

    //再写回list
    items.clear();
    setRecentGame::iterator pos = m_setGames.begin();
    for (pos; pos!=m_setGames.end(); ++pos)
    {
        items.push_back(*pos);
    }

    //打印结果
    print_result(items);
}
//stl的unique方法去重
void deduplication3(listRecentGame& items)
{
    printf("method :deduplication3
");

    //unique函数功能是去除相邻的重复元素,注意是相邻,所以必须先使用sort函数。
    items.sort();
    //unique必须重载==操作符
    listRecentGame::iterator new_end = unique(items.begin(), items.end());
    items.erase(new_end, items.end());

    //打印结果
    print_result(items);
}
//
int _tmain(int argc, _TCHAR* argv[])
{
    //装载本地记录
    tagRecentGameItem item;
    memset(&item, 0, sizeof(item));
    item.strGameCode = L"abc";
    item.strServerID = L"s31";
    item.nTime = 20160501183417;
    m_LocalList.push_back(item);

    memset(&item, 0, sizeof(item));
    item.strGameCode = L"bcd";
    item.strServerID = L"s32";
    item.nTime = 20160501183418;
    m_LocalList.push_back(item);

    memset(&item, 0, sizeof(item));
    item.strGameCode = L"cde";
    item.strServerID = L"s33";
    item.nTime = 20160501183419;
    m_LocalList.push_back(item);

    memset(&item, 0, sizeof(item));
    item.strGameCode = L"def";
    item.strServerID = L"s34";
    item.nTime = 20160501183420;
    m_RemoteList.push_back(item);

    //装载远程记录
    memset(&item, 0, sizeof(item));
    item.strGameCode = L"abc";
    item.strServerID = L"s31";
    item.nTime = 20160501183417;
    m_RemoteList.push_back(item);

    memset(&item, 0, sizeof(item));
    item.strGameCode = L"bcd";
    item.strServerID = L"s32";
    item.nTime = 20160501183418;
    m_RemoteList.push_back(item);

    memset(&item, 0, sizeof(item));
    item.strGameCode = L"cde";
    item.strServerID = L"s33";
    item.nTime = 20160501183419;
    m_RemoteList.push_back(item);

    memset(&item, 0, sizeof(item));
    item.strGameCode = L"def0";
    item.strServerID = L"s34";
    item.nTime = 20160501183420;
    m_RemoteList.push_back(item);

    //合并到一个list
    m_LocalList.insert(m_LocalList.begin(), m_RemoteList.begin(), m_RemoteList.end());

    deduplication1(m_LocalList);
    deduplication2(m_LocalList);
    deduplication3(m_LocalList);

    system("pause");

    return 0;
}

运行结果：

需要注意的地方：

STL中的排序都是默认使用小于号来排序。因此，在对结构体排序时，我们就需要重载小于号！比如：set容器在执行insert操作时，必须重载操作符<。另外，unique函数功能是去除相邻的重复元素，而在执行unique操作时必须重载操作符==。

https://blog.csdn.net/hellokandy/article/details/51333942