Compilare: user.cpp: In function ‘int main()’: user.cpp:108:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < chain.size(); ++i) { ^ user.cpp:111:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x != chain[i - 1] && i + 1 < chain.size() && ^ user.cpp:127:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < chain.size(); ++i) { ^ user.cpp:57:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("revolta.in", "rt", stdin); ^ user.cpp:58:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("revolta.out", "wt", stdout); ^ user.cpp:61:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:65:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:70:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &a, &b); ^