int main(){
while(scanf("%d", &n) == 1){
memset(used, 0, sizeof(used));
total = 0;
nQueens(0); /* Call this to start recursion */
printf("Total valid configurations for n=%d: %d\n", n,total);
}
return 0;
}
vector<vector<string> > solveNQueens(int n) {
vector<vector<string> > res;
vector<string> nQueens(n, string(n, '.'));
vector<bool> flag_col(n, false); // indicate if the column had a queen before
vector<bool> flag_45(2 * n - 1, false); // indicate if the 45° diagonal had a queen before.
vector<bool> flag_135(2 * n - 1, false); // indicate if the 135° diagonal had a queen before.
solveNQueens(res, nQueens, flag_col, flag_45, flag_135, 0, n);
return res;
}
void main(){
int n,i,j,k;
printf("\nNo of Queens : ");
scanf("%d",&n);
int x[n+1];
memset(x,0,sizeof(x));
/* x[1] = 1;
i=1,j=2,k=2;
printf("\n%d %d",place(2,1,x),place(2,2,x));
*/ nQueens(1,n,x);
}
void nQueens(int i, int n, int *x){
int j;
if(i>n){
printSol(x,n);
// exit(0);
}
for(j=1; j<=n; j++){
if(place(i,j,x)){
x[i] = j;
nQueens(i+1,n,x);
}
}
}
bool NQueens::test() {
vector<vector<int>> res = nQueens(4);
vector<int> ans1 = {1, 3, 0, 2};
vector<int> ans2 = {2, 0, 3, 1};
for (vector<int> vec : res) {
if (vec != ans1 && vec != ans2) {
cout << "Wrong ans " << endl;
cout << vec_to_string(vec) << endl;
return false;
}
}
return true;
}
void nQueens(int pos){
int i, j;
if(pos == n){
total++;
for(i = 0; i < n; i++)
printf("(%d,%d)%c", i, S[i], i == n-1 ? '\n' : ' ');
return;
}
for(i = 0; i < n; i++){
if(used[i]) continue;
for(j = 0; j < pos; j++)
if(pos-j == abs(i-S[j])) break;
if(j == pos){
S[pos] = i;
used[i] = 1;
nQueens(pos+1);
used[i] = 0;
}
}
}
