Compilare: main.cpp: In function 'int main()': main.cpp:26:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < mch[nd].size(); i++) { ~~^~~~~~~~~~~~~~~~ main.cpp:7:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pandemie.in", "r", stdin); ^ main.cpp:8:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pandemie.out", "w", stdout); ^