Compilare: main.cpp: In function 'int main()': main.cpp:36:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] #define FORN(i, n) for(int i = 0; i < (n); ++i) ^ main.cpp:115:4: note: in expansion of macro 'FORN' FORN(i, g[node].SZ) ^~~~ main.cpp:36:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] #define FORN(i, n) for(int i = 0; i < (n); ++i) ^ main.cpp:128:4: note: in expansion of macro 'FORN' FORN(i, gt[node].SZ) ^~~~ main.cpp:82:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(IN_FILE, "r", stdin); ^ main.cpp:83:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(OUT_FILE, "w", stdout); ^