Compilare: main.cpp: In function 'void Kruskal(int)': main.cpp:83:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0; i < E.size(); ++i ) ~~^~~~~~~~~~ main.cpp: In function 'void read()': main.cpp:101:15: warning: unused variable 'x' [-Wunused-variable] int i, j, x, y; ^ main.cpp:101:18: warning: unused variable 'y' [-Wunused-variable] int i, j, x, y; ^ main.cpp:102:12: warning: unused variable 'cost' [-Wunused-variable] double cost; ^~~~