学步园

//WA 了3次才AC，题目不难，但交的人不多，思想很简单，直接见代码
#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <functional>
#include <map>
using namespace std;

int main()
{	
	freopen("in.txt","r",stdin);
	vector<int> iv_s,//cluster sourse
				iv_d;//cluster destination
	
	int N,K; // 1 <= K < N <= 10000
	int si,clu;
	int sum = 0;

	cin>>N>>K;
	char* flg = new char[N+2];
	memset(flg,'0',N+2);
	flg[N+1] = '\0';

	int index = 1;
	bool bval = true;
	while(K--)
	{		
		cin>>si;
		while(si--)
		{
			cin>>clu;
			if(clu != index)//本来就在期望位置的就不需要加入移动簇表中了
			{
				bval = false;
			
				iv_s.push_back(clu);
				iv_d.push_back(index);			
			}
			flg[clu]='1';
			++index;
		}			
	}
	sum = index-1;
	if(bval == true)
	{
		cout<<"No optimization needed";
		return 0;
	}

	//cout<<&flg[1]<<endl;
	//cout<<"sum = "<<sum<<endl;
	//copy(iv_s.begin(),iv_s.end(),ostream_iterator<int>(cout," "));
	//cout<<endl;
	//copy(iv_d.begin(),iv_d.end(),ostream_iterator<int>(cout," "));
	//cout<<endl<<endl;	
	
	{
		int step = 0;
		int i = 0;
		while(iv_s.size() > 0)
		{
			bool bval = false;
			for(i = 0; i < iv_s.size();)
			{
				if(flg[ iv_d[i] ] == '0')
				{
					cout<<iv_s[i]<<" "<<iv_d[i]<<endl;
					flg[ iv_d[i] ] = '1';
					flg[ iv_s[i] ] = '0';
					bval = true;

					iv_d.erase(iv_d.begin()+i);//迭代器的使用
					iv_s.erase(iv_s.begin()+i);//找到自己的位置后，从簇表中删除
					++step;
				}
				else
					++i;
			}	

			if(bval == false)//存在死链，必须依赖空闲块进行交换
			{
				for(int i = 1; i <= N; i++)
					if(flg[i] == '0')//找到一个空闲块
					{
						cout<<iv_s[0]<<" "<<i<<endl;
						flg[ iv_s[0] ] = '0';
						iv_s[0] = i;
						flg[i] = '1';
						++step;
						break;
					}				
			}
		}

	//	cout<<endl<<"step = "<<step<<endl;
	}
	return 1;
}

测试数据：

20 3
4 2 3 11 12
1 7
3 18 5 10

8 3
3 3 4 5
3 1 2 7
1 8

6 1
3 6 3 1

4 1
3 3 2 4

8 3
3 1 2 3
3 4 5 6
1 7