Compilare: main.cpp: In function 'int main()': main.cpp:33:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<Graph[i].size(); ++j){ ~^~~~~~~~~~~~~~~~ main.cpp:12:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("amici2.in", "r", stdin); ^ main.cpp:13:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("amici2.out", "w", stdout); ^ main.cpp:14:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &T); ^ main.cpp:16:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ main.cpp:25:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^