nqueen.cpp

nqueen.cpp

#include <bits/stdc++.h>

using namespace std;

#define N 8

bool seen[N][N];
bool row[N];

int ans = 0;
void dfs(int depth)
{
	if(depth == N) {
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				printf("%d%c", seen[i][j], j == N - 1 ? '\n' : ' ');
			}
		}
		printf("\n");
		ans++;
		return;
	}

	for(int i = 0; i < N; i++) {
		bool error = false;
		if(row[i] == 0) {
			for(int j = 1; j <= depth; j++) {
				if(i - j >= 0 && seen[depth - j][i - j] == 1) {
					error = true;
					break;
				}
				if(i + j < N && seen[depth - j][i + j] == 1) {
					error = true;
					break;
				}
					
			}

			if(error)
				continue;
			seen[depth][i] = 1;
			row[i] = 1;
			dfs(depth + 1);
			seen[depth][i] = 0;
			row[i] = 0;
		}
	}
}

int main()
{
	memset(seen, false, sizeof(seen));
	memset(row, false, sizeof(row));

	dfs(0);
		
	printf("total %d\n", ans);
	return 0;
}