prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -O2 -o main.o -c main.cpp
main.cpp: In function 'bool DAG(std::vector<Node*>&, std::vector<std::map<int, int> >&)':
main.cpp:62:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<nlist.size(); i++){
                  ~^~~~~~~~~~~~~
g++ -g -Wall -O2 -o main main.o
finished

clean (3/3): 
finished

all task finished, build successfully