HDU 6185(打表代码

/** @xigua */
#include <cstdio>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <cstring>
#include <queue>
#include <set>
#include <string>
#include <map>
#include <climits>
#define PI acos(-1)
using namespace std;
typedef long long LL;
typedef double db;
const int maxn = 1e5 + ;
const int mod = 1e9 + ;
const int INF = 1e8 + ;
const LL inf = 1e15 + ;
const db eps = 1e-;
int mp[][];
int vis[][];
int n;
LL sum=;
int cnt=;

bool safe(int x, int y) {
    if (x>=&&x<&&y>=&&y<n&&!vis[x][y])  return ;
    return ;
}
bool check() {
    for (int i=; i<; i++) {
        for (int j=; j<n; j++) {
            if (!vis[i][j])  {
                return ;
            }
        }
    }
    return ;
}
int findx() {
    for (int i=; i<; i++) {
        for (int j=; j<n; j++) {
            if (!vis[i][j])  {
                return i;
            }
        }
    }
    return -;
}
int findy() {
    for (int i=; i<; i++) {
        for (int j=; j<n; j++) {
            if (!vis[i][j])  {
                return j;
            }
        }
    }
    return -;
}
void dfs(int x, int y) {
    for (int k=; k<; k++) {
        if (k==) { //1*2
            if(safe(x,y)&&safe(x+,y)) {
                vis[x][y]=, vis[x+][y]=;
                if (check())  {
                    sum++;
                    vis[x][y]=, vis[x+][y]=;
                }
                else {
                    int xx=findx(), yy=findy();
                    if(xx!=-&&yy!=-) {
                        vis[x][y]=, vis[x+][y]=;
                        dfs(xx,yy);
                        vis[x][y]=, vis[x+][y]=;
                    }
                }

            }
        }
        if (k==) {  //2*1
            if (safe(x,y)&&safe(x,y+)) {
                vis[x][y]=, vis[x][y+]=;
                    if (check())  {
                        sum++;
                        vis[x][y]=, vis[x][y+]=;
                    }
                    else {
                            vis[x][y]=, vis[x][y+]=;
                        int xx=findx(), yy=findy();
                        if(xx!=-&&yy!=-) {
                            dfs(xx,yy);
                            vis[x][y]=, vis[x][y+]=;
                        }
                    }
            }
        }
    }
}
void solve() {
    scanf("%d", &n);
    sum=;  cnt=;
    memset(vis, , sizeof(vis));
    dfs(, );
    cout<<"sum:"<<sum<<endl;
}
int main() {
    int t = , cas = ;
    //freopen("in.txt", "r", stdin);
   // freopen("out.txt", "w", stdout);
    //scanf("%d", &t);
    while(t--) {
       // printf("Case %d: ", cas++);
        solve();
    }
    return ;
}