prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -I. -O2 -std=c++11  -o main.o -c main.cpp
In file included from main.cpp:6:0:
graph.h: In constructor 'Graph::Graph(unsigned int&)':
graph.h:97:25: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int'
     subset = new Subset(_nodeNumbers);
                         ^~~~~~~~~~~~
In file included from main.cpp:5:0:
subset.h:46:1: note:   initializing argument 1 of 'Subset::Subset(int&)'
 Subset::Subset(int& _subsetSize){
 ^~~~~~
main.cpp: In function 'int main(int, char**)':
main.cpp:49:32: error: cannot bind non-const lvalue reference of type 'unsigned int&' to an rvalue of type 'unsigned int'
         Graph graph(nodeNumbers);
                                ^
In file included from main.cpp:6:0:
graph.h:83:1: note:   initializing argument 1 of 'Graph::Graph(unsigned int&)'
 Graph::Graph(unsigned int& _nodeNumbers){
 ^~~~~
Makefile:18: recipe for target 'main.o' failed
make: *** [main.o] Error 1

build failed