prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -O2 -o main.o -c main.cpp 
main.cpp: In function 'int main()':
main.cpp:178:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(n != graph.size())
        ~~^~~~~~~~~~~~~~~
g++ -g -Wall -O2 -o main main.o
finished

clean (3/3): 
finished

all task finished, build successfully