prepare (1/3): 
finished

make (2/3): 
g++ -Wall -std=c++11 -O2 -o main main.cpp
main.cpp: In function 'int main(int, const char**)':
main.cpp:50:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int node = 0; node < node_number; node++) {
                        ~~~~~^~~~~~~~~~~~~
finished

clean (3/3): 
finished

all task finished, build successfully