Compilare: main.cpp: In function 'int main()': main.cpp:47:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans.size() - 1; ++i) { ~~^~~~~~~~~~~~~~~~ main.cpp:29:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.in", "r", stdin); ^ main.cpp:30:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.out", "w", stdout); ^ main.cpp:31:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:34:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &u, &v); ^