`#include [HTML_REMOVED]
using namespace std;
const int N = 40;
int n;
char g[N][N];
bool col[N],row[N],dg[N],udg[N];
void dfs(int x,int y,int s){
if(y == n){
y = 0;
x;
}
if(x == n){
if(s == n){
for(int i = 0; i < n ; i ){
puts(g[i]);
}
cout << endl;
}
return;
}
dfs(x,y + 1,s);
//放皇后
if(!row[x] && !col[y] && !dg[x + y] && !udg[x - y + n]){
g[x][y] = ‘Q’;
row[x] = col[y] = dg[x + y] = udg[x - y + n] = true;
dfs(x,y + 1,s + 1);
row[x] = col[y] = dg[x + y] = udg[x - y + n] = false;
g[x][y] = ‘.’;
}
}
int main(){
cin >> n;
for(int i = 0; i < n; i ){
for(int j = 0; j < n; j ){
g[i][j] = ‘.’;
}
}
dfs(0,0,0);
return 0;
}`