UVa10422和UVa10085

两个题目都是类似的。八数码遍历的基本问题。

自己早先前看过八数码问题，写了一遍，不过。

后面对着解题报告，又按自己的思路写了一遍，还是不过。老是runtime error。

不知道错在哪里，调试废了我一天。哪位有心研究下能指点出来感激不尽啊。打算放弃了。因为已经了解其中的算法了。就是....神啊，求指导。呜呜。

就是模拟跳马和移动格子，然后进行广搜，用hash判重。关键是hash判重。

UVA10422：

#include<iostream>
#include<cstring>
using namespace std;
#define MaxHash 1<<25
#define Max 600000
int Hash[MaxHash];
int state[Max][25];
int goal[25]={1,1,1,1,1,0,1,1,1,1,0,0,2,1,1,0,0,0,0,1,0,0,0,0,0};
int dx[]={1,1,-1,-1,2,2,-2,-2};
int dy[]={2,-2,2,-2,1,-1,1,-1};
int dist[Max];
bool try_to_insert(int n){
	int i,ans,k;
	for(i=0,ans=0,k=0;i<25;i++){
		if(state[n][i]){
			ans+=(1<<k)*state[n][i];
			k++;
		}
	}
	ans+=1;
	if(Hash[ans])
		return false;
	else
		return true;
}
int bfs(){
	int front=1,rear=2,newx,newxy,x,y,prexy,i,newy;
	while(front<rear){
		if(dist[front]>10)
			return front;
		for(prexy=0;prexy<25;prexy++)
			if(state[front][prexy]==2)
				break;
		x=prexy/5;
		y=prexy%5;
		for(i=0;i<8;i++){
			newx=x+dx[i];
			newy=y+dy[i];
			newxy=newx*5+newy;
			if(newx>=0&&newy>=0&&newx<5&&newy<5){
				memcpy(state[rear],state[front],sizeof(state[front]));
				state[rear][prexy]=state[front][newxy];
				state[rear][newxy]=state[front][prexy];
				dist[rear]=dist[front]+1;
				if(try_to_insert(rear)){
					if(memcmp(state[rear],goal,sizeof(goal))==0)
						return rear;
					rear++;
				}
			}
		}
		front++;
	}
	return 0;
}
int main(){
	int test_case,steps;
	char str[6];
	cin >> test_case;
	cin.get();
	while(test_case--){
		memset(Hash,0,sizeof(Hash));
		memset(dist,0,sizeof(dist));
		for(int i=0,k=0;i<5;i++){
			cin.getline(str,6);
			for(int j=0;j<5;j++){
				if(str[j]=='1')
					state[1][k++]=1;
				else if(str[j]=='0')
					state[1][k++]=0;
				else
					state[1][k++]=2;
			}
		}
		if(memcmp(state[1],goal,sizeof(goal))!=0)
			steps=bfs();
		else{
			cout << "Solvable in 0 move(s).\n";
		}
		if(dist[steps]<11)
			cout << "Solvable in " << dist[steps] << " move(s).\n";
		else
			cout << "Unsolvable in less than 11 move(s).";
	}
	return 0;
}

UVa10085:

#include<iostream>
#include<string>
#include<cstring>
using namespace std;
const int Maxstate=100000;
const int MaxHashTable=1000003;
struct Node{
	int state[9];
	string str;
};
Node st[Maxstate];
int head[MaxHashTable],Next[Maxstate];
int dx[]={1,-1,0,0};
int dy[]={0,0,-1,1};
char path[]="DULR";
int Hash(Node s){
	int i,v;
	for(i=0,v=0;i<9;i++)
		v=v*10+s.state[i];
	return v%MaxHashTable;
}
bool try_to_insert(int n){
	int h=Hash(st[n]);
	int u=head[h];
	while(u){
		if(memcmp(st[u].state,st[n].state,sizeof(st[u].state))==0)
			return false;
		u=Next[u];
	}
	Next[n]=head[h];
	head[h]=n;
	return true;
}
int bfs(void){
	int rear,front,i,x,y,prexy,newxy,newx,newy;
	front=1;
	rear=2;
	while(front<rear){
		Node &s=st[front];
		for(prexy=0;prexy<9;prexy++){
			if(!s.state[prexy])
				break;
		}
		x=prexy/3;
		y=prexy%3;
		for(i=0;i<4;i++){
			newx=x+dx[i];
			newy=y+dy[i];
			st[rear].str=st[front].str+path[i];
			newxy=newx*3+newy;
			if(newx>=0&&newy>=0&&newx<3&&newy<3){
				Node &t=st[rear];
				memcpy(t.state,s.state,sizeof(s.state));
				t.state[prexy]=s.state[newxy];
				t.state[newxy]=s.state[prexy];
				if(try_to_insert(rear))
					rear++;
			}
		}
		front++;
	}
	return rear;
}
int main()
{
	int test_case,i,j,num_case=0,rear;
	cin >> test_case;
	cin.get();
	while(test_case--){
		num_case++;
		cout << "Puzzle #" << num_case << endl;
		memset(st,0,sizeof(st));
		memset(head,0,sizeof(head));
		memset(Next,0,sizeof(Next));
		for(i=0;i<9;i++)
			cin>>st[1].state[i];
		try_to_insert(1);
		rear=bfs();
		for(i=0;i<3;i++){
			for(j=0;j<3;j++){
				cout << st[rear].state[i*3+j];
			}
			cout << endl;
		}
		cout << st[rear].str << endl;
	}
	return 0;
}