Compilare: main.cpp: In function 'int main()': main.cpp:49:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < graph[u].size(); j++) { ~~^~~~~~~~~~~~~~~~~ main.cpp:21:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("amici.in", "r", stdin); ^ main.cpp:22:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("amici.out", "w", stdout); ^ main.cpp:23:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &test); ^ main.cpp:28:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:35:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^