[골5] 24891 - 단어 마방진

#include <iostream>
#include <algorithm>
#include <string>
#include <vector>

#define FAST_IO() \
{\
	ios::sync_with_stdio(false);\
	cin.tie(NULL); \
	cout.tie(NULL); \
}\

using namespace std;

vector<string> ans(20), s(20);
vector<bool> vis(20);
int l, n;

void DFS(int cnt = 0)
{
	if (cnt == l)
	{
		bool flag = true;

		for (int i = 0; i < l; i++)
		{
			for (int j = i + 1; j < l; j++)
			{
				if (flag)
					flag = (ans[i][j] == ans[j][i]);
			}
		}
		if (flag)
		{
			for (int i = 0; i < l; i++)
			{
				for (int j = 0; j < l; j++)
					cout << ans[i][j];

				cout << "\n";
			}
			exit(0);
		}
		return;
	}
	for (int i = 0; i < n; i++)
	{
		// 백트래킹
		if (!vis[i])
		{
			vis[i] = true;
			ans[cnt] = s[i];
			DFS(cnt + 1);
			vis[i] = false;
		}
	}
}

int main()
{
	FAST_IO();
	cin >> l >> n;

	for (int i = 0; i < n; i++)
		cin >> s[i];

	sort(s.begin(), s.begin() + n);
	DFS();
	cout << "NONE";

	return 0;
}