cmake

set(CMAKE_BUILD_TYPE "Release")

if( CMAKE_BUILD_TYPE STREQUAL "Debug" )

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -g -Wall -Wno-unused-variable -pthread")

else( CMAKE_BUILD_TYPE STREQUAL "Debug" )

set(CMAKE_BUILD_TYPE "Release")

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -O2 -pthread -fopenmp")

endif( CMAKE_BUILD_TYPE STREQUAL "Debug" )

message("Build Type:"${CMAKE_BUILD_TYPE} ${CMAKE_CXX_FLAGS})

debug模式下,加-Os，速度会快

Release模式下，加 -O2,和不加，有比较显著的差异