Compilare: user.cpp: In function ‘void reset(std::vector<int>, int, int)’: user.cpp:81:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < chn.size(); i++) ^ user.cpp:87:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < chn.size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:133:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("magic.in", "r", stdin); ^ user.cpp:134:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("magic.out", "w", stdout); ^ user.cpp:137:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &n); ^ user.cpp:140:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:145:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^