【SCOI 2005】 骑士精神

【题目链接】

https://www.lydsy.com/JudgeOnline/problem.php?id=1085

【算法】

IDA*

【代码】

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

int i,j,T,x,y,step;
char c;
bool solved;
int mp[][];

inline bool valid(int x,int y)
{
        return x >=  && x <  && y >=  && y < ;
}
inline int f()
{
        int i,j;
        int ret = ;
        for (i = ; i < ; i++)
        {
                for (j = ; j < ; j++)
                {
                        if (mp[i][j] != goal[i][j])
                                ret++;
                }
        }
        return ret - ;
}

inline bool IDDFS(int dep,int x,int y)
{
        int i,tx,ty;
        if (dep + f() > step) return false;
        if (dep == step) return true;
        for (i = ; i < ; i++)
        {
                tx = x + dx[i];
                ty = y + dy[i];
                if (valid(tx,ty))
                {
                        swap(mp[x][y],mp[tx][ty]);
                        if (IDDFS(dep+,tx,ty)) return true;
                        swap(mp[x][y],mp[tx][ty]);
                }
        }
        return false;
}

int main()
{

        scanf("%d",&T);
        getchar();
        while (T--)
        {
                solved = false;
                for (i = ; i < ; i++)
                {
                        for (j = ; j < ; j++)
                        {
                                c = getchar();
                                if (c == '')    mp[i][j] = ;
                                else if (c == '') mp[i][j] = ;
                                else
                                {
                                        x = i;
                                        y = j;
                                        mp[i][j] = ;
                                }
                        }
                        getchar();
                }
                for (i = ; i <= ; i++)
                {
                        step = i;
                        if (IDDFS(,x,y))
                        {
                                printf("%d\n",i);
                                solved = true;
                                break;
                        }
                }
                if (!solved) printf("-1\n");
        }

        return ;

}