51| 八皇后

代码实现

#include <bits/stdc++.h>
using namespace std;

int n;
const int N = 15;
bool st[N], st1[2*N], st2[2*N];
vector <int> path;
int ret;
void dfs(int x)
{
	if (x > n)
	{
		ret++;
		if(ret <= 3)
		{
			for (auto x : path) cout << x << " ";
			cout << endl;			
		}
		return ;
	}
	for (int y = 1; y <= n; y++)
	{
		if (st[y] || st1[y-x+n] || st2[y+x] ) continue;
		st[y] = st1[y-x+n] = st2[y+x] = true;
		path.push_back(y);
		dfs(x+1);
		st[y] =  st1[y-x+n] = st2[y+x] = false;
		path.pop_back();
	}
 } 
int main ()
{
	cin >> n;
	dfs(1);
	cout << ret << endl;
	return 0;
 }