HDU1253 胜利大逃亡 dfs

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int n,m,l,t,ans;
int v[55][55][55];
int map[55][55][55];
int yi[6][3]={{1,0,0},{-1,0,0},{0,1,0},{0,-1,0},{0,0,1},{0,0,-1}};
void dfs(int x,int y,int z,int time)
{
    if (time>t||time>=ans) return ;
    if (m+n+l-x-y-z>t-time) return ;
    if (x==n-1&&y==m-1&&z==l-1) {ans=time;return ;}
    int rx,ry,rz,i;
    for (i=0;i<6;i++)
    {
        rx=x+yi[i][0];
        ry=y+yi[i][1];
        rz=z+yi[i][2];
        if (rx>=0&&rx<n&&ry>=0&&ry<m&&rz>=0&&rz<l&&map[rx][ry][rz]!=1&&(v[rx][ry][rz]==0||time<v[rx][ry][rz]))
        {
            v[rx][ry][rz]=time;
            map[rx][ry][rz]=1;
            dfs(rx,ry,rz,time+1);
            map[rx][ry][rz]=0;
        }
    }
}
int main()
{
    int c,i,j,k;
    scanf("%d",&c);
    while (c--)
    {
        scanf("%d%d%d%d",&n,&m,&l,&t);
        for (i=0;i<n;i++)
        for (j=0;j<m;j++)
        for (k=0;k<l;k++) scanf("%d",&map[i][j][k]);
        ans=1001;
        memset(v,0,sizeof(v));
        dfs(0,0,0,0);
        if (ans==1001) printf("-1\n");
        else printf("%d\n",ans);
    }
    return 0;
}