Compiler output
prog.cpp: In function 'void df(int)':
prog.cpp:20:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0; i<v[nod].size(); ++i)
^
prog.cpp: In function 'void df2(int)':
prog.cpp:33:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0; i<vi[nod].size(); ++i)
^
prog.cpp: In function 'int main()':
prog.cpp:58:12: warning: unused variable 'elapsed_secs' [-Wunused-variable]
double elapsed_secs = double(end - st) / CLOCKS_PER_SEC;
^