C++高质量问答精选
https://stackoverflow.com/questions/21204676/modern-way-to-filter-stl-container
https://stackoverflow.com/questions/4303513/push-back-vs-emplace-back
https://stackoverflow.com/questions/21204676/modern-way-to-filter-stl-container
https://stackoverflow.com/questions/4303513/push-back-vs-emplace-back