UVA - 211（网格转化为线性dfs）

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;

const int N = 7;
const int M = 8;
int maze[N*M];
int image[N*M],id[N][N];
bool use[M][M],vis[N*M];

int ALL;
void print_ans(){
  ALL++;
  printf("\n");
  for(int i=0;i<N;i++){
     for(int j=0;j<M;j++){
       printf("%4d",image[M*i+j]);
  }
  printf("\n");
  }
}
void dfs(int posi){
if(posi+M<56&&!vis[posi+M]){
    int x=maze[posi],y=maze[posi+M];
    if(x>y) swap(x,y);
    if(!use[x][y]){
        use[x][y]=true;
        vis[posi]=vis[posi+M]=true;
        image[posi]=id[x][y];
        image[posi+M]=id[x][y];
        for(int i=posi+1;i<56;i++){
            if(!vis[i]){
                dfs(i); break;
            }
            if(i==55) print_ans();
        }
        use[x][y]=false;
        vis[posi]=vis[posi+M]=false;
    }
}

if((posi+1)%M!=0&&!vis[posi+1]){
    int x=maze[posi],y=maze[posi+1];
    if(x>y) swap(x,y);
    if(!use[x][y]){
        use[x][y]=true;
        vis[posi]=vis[posi+1]=true;
        image[posi]=id[x][y];
        image[posi+1]=id[x][y];
        for(int i=posi+1;i<56;i++){
            if(!vis[i]){
                dfs(i); break;
            }
            if(i==55) print_ans();
        }
        use[x][y]=false;
        vis[posi]=vis[posi+1]=false;
    }
}
}
int main()
{
    int num=1;
    for(int i=0;i<=6;i++)
      for(int j=i;j<=6;j++){
          //cout<<i<<" "<<j<<" "<<num<<endl;
          id[i][j]=num++;
    }

    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif // ONLINE_JUDGE
    memset(vis,false,sizeof(vis));
    memset(use,false,sizeof(use));
    int kase=1;
    while(scanf("%d",&maze[0])==1){
        if(kase!=1) printf("\n\n\n");
        for(int i=1;i<56;i++) scanf("%d",&maze[i]);
        printf("Layout #%d:\n\n",kase);
        for(int i=0;i<N;i++){
           for(int j=0;j<M;j++){
              printf("%4d",maze[M*i+j]);
           }
                printf("\n");
           }
        ALL=0;
        printf("\nMaps resulting from layout #%d are:\n",kase);
        dfs(0);
        printf("\nThere are %d solution(s) for layout #%d.\n",ALL,kase++);
    }
    return 0;
}