POJ2225Asteroids![Depth first search]

3 dimensional Depth frist search

#include<stdio.h>#include<queue>#include<iostream>#include<string.h>using namespace std;char s[10];int f[20][20][20],p[20][20][20],x1,x2,y1,y2,z1,z2,i,j,n;void dfs(int x,int y,int z,int w){    if(p[x][y][z]<=w)return;//Prune     if(!f[x][y][z])return;//Boundary condition     p[x][y][z]=w;//Update     dfs(x+1,y,z,w+1);    dfs(x,y+1,z,w+1);    dfs(x,y,z+1,w+1);    dfs(x-1,y,z,w+1);    dfs(x,y-1,z,w+1);    dfs(x,y,z-1,w+1);//Continue}int main(){    while(scanf("%s",s)!=EOF){        scanf("%d",&n);        getchar();        memset(f,0,sizeof(f));        for(i=1;i<=n;i++)            for(j=1;j<=n;j++,getchar())                for(int o=1;o<=n;o++)                    if(getchar()=='O')f[o][j][i]=1;        for(i=1;i<=n;i++)            for(j=1;j<=n;j++)                for(int o=1;o<=n;o++)                    p[i][j][o]=0x3ffffff;//Init        scanf("%d%d%d%d%d%d",&x1,&y1,&z1,&x2,&y2,&z2);        x1++;        x2++;        y1++;        y2++;        z1++;        z2++;//Because first number if 0        scanf("%s",s);//Read "END"        dfs(x1,y1,z1,0);        if(p[x2][y2][z2]==0x3ffffff)puts("NO ROUTE");        else printf("%d %d\n",n,p[x2][y2][z2]);    }    return 0;}