8 位数码难题的问题求解

#include<iostream>
#include<string>
#include<string.h>
#include<queue>
#include<set>
#include<algorithm>
using namespace std;
struct node{
	int x,y;
	int step;//步数
	char pre;//前一步操作U`D`L`R  ps:上一步操作是U，那么下一步操作不能是D，因为会产生死循环..
	char map[5][5]; //九宫地图
	char path[10000];//记录路径
};//可理解为当前状态地图信息-结构体
char begin[5][5],over[5][5];//开始地图和结束地图 已知.
int x1,y1;//记录空格坐标
void swap(int *a,int *b)
{
	int *t;
	*t=*a;
	*a=*b;
	*b=*t;
}
bool check(node a)
{
	int i,j;
	for(i=0;i<3;i++)
		for(j=0;j<3;j++)
		{
			if(a.map[i][j]!=over[i][j])
				return false;
		}
	return true;
}
set<string> hsh;
bool getvis(node a)
{
	string tmp="";
	int i,j;
	for(i=0;i<3;i++)
		for(j=0;j<3;j++)
		{
			tmp+=a.map[i][j];
		}
	if(hsh.find(tmp)!=hsh.end())//如果找到有相同的排序，那么不可进入字符串数组hsh 隐含地把用更多步数而得到相同排序的情况排除！
		return false;

	hsh.insert(tmp);
	return true;
}
void pfMapPath(node tmp)
{
	int i,j,k;
	cout<<"初始状态"<<endl;
	for(i=0;i<3;i++)
	{
		for(j=0;j<3;j++)
		{
			if(begin[i][j]=='0')
			{
				tmp.map[i][j]=' ';
				cout<<"  ";
			}
			else
			{
				tmp.map[i][j]=begin[i][j];
				cout<<begin[i][j]<<" ";
			}
		}
		cout<<endl;
	}
	cout<<endl;
	
	for(i=1;i<=tmp.step;i++)
	{
		if(tmp.path[i]=='U')
		{
			cout<<"前一状态走向:U"<<" 第"<<i<<"个状态:"<<endl;
			swap(tmp.map[x1][y1],tmp.map[x1-1][y1]);
			x1--;
			for(j=0;j<3;j++)
			{
				for(k=0;k<3;k++)
				{
					if(tmp.map[j][k]=='0')
					{
						cout<<"  ";
					}
					else
					{
						cout<<tmp.map[j][k]<<" ";
					}
				}
				cout<<endl;
			}
		}
		else if(tmp.path[i]=='D')
		{
			cout<<"前一状态走向:D"<<" 第"<<i<<"个状态:"<<endl;
			swap(tmp.map[x1][y1],tmp.map[x1+1][y1]);
			x1++;
			for(j=0;j<3;j++)
			{
				for(k=0;k<3;k++)
				{
					if(tmp.map[j][k]=='0')
					{
						cout<<"  ";
					}
					else
					{
						cout<<tmp.map[j][k]<<" ";
					}
				}
				cout<<endl;
			}
		}
		else if(tmp.path[i]=='R')
		{
			cout<<"前一状态走向:R"<<" 第"<<i<<"个状态:"<<endl;
			swap(tmp.map[x1][y1],tmp.map[x1][y1+1]);
			y1++;
			for(j=0;j<3;j++)
			{
				for(k=0;k<3;k++)
				{
					if(tmp.map[j][k]=='0')
					{
						cout<<"  ";
					}
					else
					{
						cout<<tmp.map[j][k]<<" ";
					}
				}
				cout<<endl;
			}
		}
		else if(tmp.path[i]=='L')
		{
			cout<<"前一状态走向:L"<<" 第"<<i<<"个状态:"<<endl;
			swap(tmp.map[x1][y1],tmp.map[x1][y1-1]);
			y1--;
			for(j=0;j<3;j++)
			{
				for(k=0;k<3;k++)
				{
					if(tmp.map[j][k]=='0')
					{
						cout<<"  ";
					}
					else
					{
						cout<<tmp.map[j][k]<<" ";
					}
				}
				cout<<endl;
			}
		}
	}
	cout<<"终止状态:"<<endl;
	for(i=0;i<3;i++)
	{
		for(j=0;j<3;j++)
		{
			if(over[i][j]=='0')
			{
				cout<<"  ";
			}
			else
			{
				cout<<over[i][j]<<" ";
			}
		}
		cout<<endl;
	}
}
bool bfs(int x,int y)
{
	node start;
	start.x=x;
	start.y=y;
	start.step=0;
	start.pre='X';
	int i,j;
	for(i=0;i<3;i++)
		for(j=0;j<3;j++)
			start.map[i][j]=begin[i][j];
	queue<node> q;
	q.push(start);
	while(!q.empty())
	{
		node tmp=q.front(),tmp1;
		q.pop();
		if(check(tmp))
		{
			cout<<tmp.step<<endl;
			return true;
		}
		tmp1=tmp;
		if(tmp1.pre!='U'&&tmp1.x+1<3)
		{
			tmp1.path[tmp1.step]=tmp1.pre;
			tmp1.pre='D';
			tmp1.step++;
			swap(tmp1.map[tmp1.x][tmp1.y],tmp1.map[tmp1.x+1][tmp1.y]);
			tmp1.x++;
			if(getvis(tmp1))
			{
				if(check(tmp1))
				{
					tmp1.path[tmp1.step]=tmp1.pre;
					pfMapPath(tmp1);
					//	cout<<tmp1.step<<endl;
					return true;
				}
				else
				{
					q.push(tmp1);
				}
			}
		}
		tmp1=tmp;
		if(tmp1.pre!='D'&&tmp1.x-1>=0)
		{
			tmp1.path[tmp1.step]=tmp1.pre;
			tmp1.pre='U';
			tmp1.step++;
			swap(tmp1.map[tmp1.x][tmp1.y],tmp1.map[tmp1.x-1][tmp1.y]);
			tmp1.x--;
			if(getvis(tmp1))
			{
				if(check(tmp1))
				{
					tmp1.path[tmp1.step]=tmp1.pre;
					pfMapPath(tmp1);
					//	cout<<tmp1.step<<endl;
					return true;
				}
				else
				{
					q.push(tmp1);
				}
			}
		}
		tmp1=tmp;
		if(tmp1.pre!='L'&&tmp1.y+1<3)
		{
			tmp1.path[tmp1.step]=tmp1.pre;
			tmp1.pre='R';
			tmp1.step++;
			swap(tmp1.map[tmp1.x][tmp1.y],tmp1.map[tmp1.x][tmp1.y+1]);
			tmp1.y++;
			if(getvis(tmp1))
			{
				if(check(tmp1))
				{
					tmp1.path[tmp1.step]=tmp1.pre;
					pfMapPath(tmp1);
					//	cout<<tmp1.step<<endl;
					return true;
				}
				else
				{
					q.push(tmp1);
				}
			}
		}
		tmp1=tmp;
		if(tmp1.pre!='R'&&tmp1.y-1>=0)
		{
			tmp1.path[tmp1.step]=tmp1.pre;
			tmp1.pre='L';
			tmp1.step++;
			swap(tmp1.map[tmp1.x][tmp1.y],tmp1.map[tmp1.x][tmp1.y-1]);
			tmp1.y--;
			if(getvis(tmp1))
			{
				if(check(tmp1))
				{
					tmp1.path[tmp1.step]=tmp1.pre;
					pfMapPath(tmp1);
					//	cout<<tmp1.step<<endl;
					return true;
				}
				else
				{
					q.push(tmp1);
				}
			}
		}
	}
	return false;
}
int main()
{
	char str[100];
	cin>>str;
	int x,y;//记录空格坐标
	int i,j;
	for(i=0;i<3;i++){
		for(j=0;j<3;j++)
		{
			if(str[i*3+j]=='.')
			{
				x=i;
				y=j;
				x1=x;
				y1=y;
				begin[i][j]='0';
			}
			else
				begin[i][j]=str[i*3+j];
		}
	}
	cin>>str;
	for(i=0;i<3;i++){
		for(j=0;j<3;j++)
		{
			if(str[i*3+j]=='.')
				over[i][j]='0';
			else
				over[i][j]=str[i*3+j];
		}
	}
	if(!bfs(x,y))
		cout<<"-1"<<endl;
	return 0;
}