Compilare: main.cpp: In function 'void Kruskal(bool)': main.cpp:45:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i==v.size()-2 && !isFirst) ~^~~~~~~~~~~~ main.cpp:57:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v.size();i++) ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:69:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("online.in", "r", stdin); ^ main.cpp:70:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("online.out", "w", stdout); ^ main.cpp:72:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:76:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &c); ^ main.cpp:81:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &k); ^ main.cpp:84:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &c); ^