Compilare: main.cpp: In function 'int calc_min_diff(int&, int&)': main.cpp:177:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = pos; j < v[r].size(); ++j) ~~^~~~~~~~~~~~~ main.cpp: In function 'int32_t main()': main.cpp:198:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(PROB_NAME".in", "r", stdin); ^ main.cpp:199:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(PROB_NAME".out", "w", stdout); ^