improved vector_test.cpp
improved vector_test.cpp

alesiong/CUHKSZLib,alesiong/CUHKSZLib,cuhkshenzhen/CUHKSZLib,alesiong/CUHKSZLib,Yexiaoxing/CUHKSZLib,cuhkshenzhen/CUHKSZLib,Yexiaoxing/CUHKSZLib,cuhkshenzhen/CUHKSZLib,Yexiaoxing/CUHKSZLib