prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -O2 -std=c++11 -o main.o -c main.cpp
g++ -g -Wall -O2 -std=c++11 -o graph.o -c graph.cpp
graph.cpp: In member function 'int Graph::PrimMST()':
graph.cpp:86:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i < this->vertices; ++i) {
                     ~~^~~~~~~~~~~~~~~~
g++ -g -Wall -O2 -std=c++11 -o main main.o graph.o
finished

clean (3/3): 
finished

all task finished, build successfully