【HAOI 2008】 移动玩具

【题目链接】

https://www.lydsy.com/JudgeOnline/problem.php?id=1054

【算法】

广度优先搜索

【代码】

#include<bits/stdc++.h>
using namespace std;
const int dx[] = {,,-,};
const int dy[] = {-,,,};
const int MAXS =  << ;

struct info
{
        int mp[][];
        int step;
} ;

int i,j,k,goal,tx,ty,l,r,state;
int mp[][],g[][];
info q[MAXS];
info cur,tmp;
bool visited[MAXS];

inline bool valid(int x,int y)
{
        return x >  && x <=  && y >  && y <= ;
}
inline int get(int a[][])
{
        int i,j,ret = ;
        int b = ;
        for (i = ; i <= ; i++)
        {
                for (j = ; j <= ; j++)
                {
                        ret += a[i][j] * b;
                        b <<= ;
                }
        }
        return ret;
}

int main()
{

        for (i = ; i <= ; i++)
        {
                for (j = ; j <= ; j++)
                {
                        mp[i][j] = getchar() - '';
                }
                getchar();
        }
        getchar();
        for (i = ; i <= ; i++)
        {
                for (j = ; j <= ; j++)
                {
                        g[i][j] = getchar() - '';
                }
                getchar();
        }
        goal = get(g);
        visited[get(mp)] = true;
        if (visited[goal])
        {
                printf("0\n");
                return ;
        }
        l = r = ;
        memcpy(q[].mp,mp,sizeof(q[].mp));
        q[].step = ;
        while (l <= r)
        {
                cur = q[l];
                l++;
                for (i = ; i <= ; i++)
                {
                        for (j = ; j <= ; j++)
                        {
                                if (cur.mp[i][j] == )
                                {
                                        for (k = ; k < ; k++)
                                        {
                                                tx = i + dx[k];
                                                ty = j + dy[k];
                                                if (valid(tx,ty) && cur.mp[tx][ty] == )
                                                {
                                                        swap(cur.mp[i][j],cur.mp[tx][ty]);
                                                        state = get(cur.mp);
                                                        if (!visited[state])
                                                        {
                                                                visited[state] = true;
                                                                if (state == goal)
                                                                {
                                                                        printf("%d\n",cur.step+);
                                                                        return ;
                                                                }
                                                                r++;
                                                                memcpy(q[r].mp,cur.mp,sizeof(q[r].mp));
                                                                q[r].step = cur.step + ;
                                                        }
                                                        swap(cur.mp[i][j],cur.mp[tx][ty]);
                                                }
                                        }
                                }
                        }
                }
        }

        return ;

}