Compilare: main.cpp: In function 'void backTrack(int, long long int&)': main.cpp:12:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p == lst[0].size()) { ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:40:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("culori4.in", "r", stdin); ^ main.cpp:41:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("culori4.out", "w", stdout); ^