Daddy's Journey to Platinum

/// n-th queen location check
int backtrack(vector<string> board, int nQueen )
{
	if(nQueen == 8)
        return 1;

	int ans=0;
	for (int i = 0; i < 8; ++i)
	{
		if(board[nQueen][i]=='.'){
			vector<string> n_board = board;
			for (int j = nQueen; j < 8; ++j) /// only check below rows
			{
				n_board[j][i]='*';
				if(i-j+nQueen>=0)
					n_board[j][i-(j-nQueen)]='*'; /// diagonal
				if(i+j-nQueen<8)
					n_board[j][i+(j-nQueen)]='*'; /// diagonal
			}
			ans += backtrack(n_board,nQueen+1);   /// updated board , next row
		}
	}
	return ans;
}

int main()
{
    vector <string> board;

    for (int i = 0; i < 8; i++)
    {
        string tmp;
        cin >> tmp;
        board.push_back(tmp);
    }

    int ways = backtrack(board, 0);

long ans = 1e18;

void search_diff(int a, long b, vector<int> weight)
{
    if (a == weight.size()) {
        ans = min(ans, abs(b));
        return;
    }
    search_diff(a+1,b+weight[a], weight);	/// add apple to side A
    search_diff(a+1,b-weight[a], weight);	/// add apple to side B
}

int main()
{
    int N;		/// number of apple

    vector<int> weight(N,0);
    for(int idx=0; idx<N ; ++idx)
        cin >> weight[idx];

    search_diff(0,0, weight);

    cout << ans << endl;