Compilare: main.cpp: In function 'int main()': main.cpp:33:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<v.size() - 1; i++){ ~^~~~~~~~~~~~~ main.cpp:36:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j < v.back().size(); j++) u &= (v[i][j] == v.back()[j]); ~~^~~~~~~~~~~~~~~~~ main.cpp:15:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("brazi.in", "r", stdin); ^ main.cpp:16:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("brazi.out", "w", stdout); ^ main.cpp:17:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ main.cpp:19:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^