delete pics to save space

1.1219.cpp

@@ -0,0 +1,31 @@
+#include<cstdio>
+#include<cstring>
+int n,cnt;
+int res[20];
+void dfs(int step,int a,int b,int c)
+{
+	if(step>=n)
+	{
+		if(cnt++<3)
+		{
+			printf("%d",res[0]);
+			for(int i=1;i<n;i++) printf(" %d",res[i]);
+			printf("\n");
+		}
+		return;
+	}
+	int cant=a|b|c;
+	for(int i=1;i<=n;i++)
+		if(!(cant&(1<<i)))
+		{
+			res[step]=i;
+			dfs(step+1,a|(1<<i),(b|(1<<i))<<1,(c|(1<<i))>>1);
+		}
+}
+int main()
+{
+	scanf("%d",&n);
+	dfs(0,0,0,0);
+	printf("%d\n",cnt);
+	return 0;
+}