Vector<bool>?

https://leetcode.com/problems/n-queens/discuss/19808/Accepted-4ms-c++-solution-use-backtracking-and-bitmask-easy-understand./20103

In fact, vector<bool> is not a STL container. You should avoid to use it. You can also get the knowledge from http://stackoverflow.com/questions/17794569/why-is-vectorbool-not-a-stl-container and http://stackoverflow.com/questions/670308/alternative-to-vectorbool