[hdu 1067]bfs+hash

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1067

queue里面果然不能放vector，还是自己写的struct比较省内存……

#include<bits/stdc++.h>
using namespace std;

int a[][];
const int INF=0x3f3f3f3f;
const int p=;
const int md=;

struct Node
{
    int a[][];
    Node(){}
    Node(const int x[][])
    {
        for (int i=;i<;i++)
            for (int j=;j<;j++)
                a[i][j]=x[i][j];
    }
    int gethash() const
    {
        int now=;
        for (int i=;i<;i++)
            for (int j=;j<;j++)
                now=(1ll*now*p%md+a[i][j])%md;
        return now;
    }
};

const int End[][]=
{
    {,,,,,,,},
    {,,,,,,,},
    {,,,,,,,},
    {,,,,,,,}
};

const Node endNode(End);

const int term=endNode.gethash();

unordered_map<int,int> M;

queue<Node> q;

int bfs()
{
    M.clear();
    while (!q.empty()) q.pop();
    for (int i=;i<;i++)
        for (int j=;j<;j++)
            if (a[i][j]%==)
            {
                int tmp=a[i][j];
                a[i][j]=;
                a[tmp/-][]=tmp;
            }
    Node tmp;
    for (int i=;i<;i++) for (int j=;j<;j++) tmp.a[i][j]=a[i][j];
    q.push(tmp);
    int H=tmp.gethash();
    if (H==term) return ;
    M[H]=;
    while (!q.empty())
    {
        Node now=q.front();
        int st=M[now.gethash()];
        q.pop();
        for (int i=;i<;i++)
            for (int j=;j<;j++)
                if (now.a[i][j]== && now.a[i][j-]%!=)
                {
                    int tar=now.a[i][j-]+;
                    int K=-;
                    for (int I=;I<;I++)
                    {
                        for (int J=;J<;J++)
                        {
                            if (now.a[I][J]==tar)
                            {
                                K=I*+J;
                                break;
                            }
                        }
                        if (K!=-) break;
                    }
                    now.a[i][j]=tar;
                    now.a[K/][K%]=;
                    int H=now.gethash();
                    if (!M.count(H))
                    {
                        if (H==term) return st+;
                        q.push(now);
                        M[H]=st+;
                    }
                    now.a[i][j]=;
                    now.a[K/][K%]=tar;
                }
    }
    return INF;
}

int main()
{
    int t;
    scanf("%d",&t);
    while (t--)
    {
        for (int i=;i<;i++)
            for (int j=;j<;j++)
                scanf("%d",&a[i][j]);
        int ans=bfs();
        if (ans!=INF) printf("%d\n",ans);
        else printf("-1\n");
    }
    return ;
}