#include #include #include #define MAX 110 using namespace std; int n; int sum; int ans[MAX]; int vis[3][MAX];///vis[0]代表列，vis[1]代表副对角线，vis[2]代表主对角线 void DFS(int x) { int i; if(xn+1) { sum++; if(sum<=3) { for(i=1; i<=n; i++) { if(i1) { printf("%d",ans[i]); } else { printf(" %d",ans[i]); } } printf("\n"); return ;
}
} for(i=1; i<=n; i++) { if(!vis[0][i]&&!vis[1][x+i]&&!vis[2][x-i+n]) { vis[0][i]=vis[1][x+i]=vis[2][x-i+n]=1; ans[x]=i; DFS(x+1); vis[0][i]=vis[1][x+i]=vis[2][x-i+n]=0;///状态恢复 } } } int main() { scanf("%d",&n); memset(ans,0,sizeof(ans)); memset(vis,0,sizeof(vis)); DFS(1); printf("%d\n",sum); }

#include<cstdio>
using namespace std;
int n;
int temp[50];
int ass[5][100],ansnum;
bool zuoshang[50],zuoxia[50];//zuoshang为\，zuoxia为/ 
bool liel[50],hangh[50];
int dfs(int hang);
int main()
{
	freopen("checker.in","r",stdin);
	freopen("checker.out","w",stdout);
	scanf("%d",&n);
	dfs(1);
	for (int i=1;i<=3;i++)
	{
		for (int j=1;j<=n;j++)
			printf("%d ",ass[i][j]);
		printf("\n");
	}
	printf("%d",ansnum);
	return 0;
}
int dfs(int hang)//现在在搜索第hang行 
{
	for (int i=1;i<=n;i++)//在n列里面找位置 
	{
		if (zuoshang[hang-i+n]==false&&zuoxia[hang+i]==false&&liel[i]==false)
		{
			zuoshang[hang-i+n]=true;
			zuoxia[hang+i]=true;
			liel[i]=true;
			temp[hang]=i;
			if (hang<=n-1)
			{
				temp[hang]=i;
				dfs(hang+1);
			} 
			else
			{
				temp[hang]=i;
				ansnum++;
				if (ansnum<=3)
				{
					for (int j=1;j<=n;j++)
					{
						ass[ansnum][j]=temp[j];
					}
				}
			}
			zuoshang[hang-i+n]=false;
			zuoxia[hang+i]=false;
			liel[i]=false;
		}
	}
}