Compilare: main.cpp: In function 'int main()': main.cpp:95:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( k = 0 ; k < l [ j ].size() ; ++ k ) { ~~^~~~~~~~~~~~~~~~ main.cpp:117:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( j = 0 ; j < l [ lmax ].size() ; ++ j ) ans += l [ lmax ][ j ].s.f * l [ lmax ][ j ].s.s % MOD , ans %= MOD ; ~~^~~~~~~~~~~~~~~~~~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:32:29: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^ main.cpp: In function 'int main()': main.cpp:4:11: warning: 'way' may be used uninitialized in this function [-Wmaybe-uninitialized] #define s second ^~~~~~ main.cpp:82:32: note: 'way' was declared here int64_t i , j , k , dist , way ; ^~~