Compilare: user.cpp: In function ‘int main()’: user.cpp:64:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nustiu.in", "r", stdin); ^ user.cpp:65:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nustiu.out", "w", stdout); ^ In file included from /usr/include/string.h:642:0, from /usr/include/c++/4.8/cstring:42, from /usr/include/i386-linux-gnu/c++/4.8/bits/stdc++.h:48, from user.cpp:1: In function ‘void* memset(void*, int, size_t)’, inlined from ‘int BFS(int)’ at user.cpp:16:31: /usr/include/i386-linux-gnu/bits/string3.h:85:70: warning: call to void* __builtin___memset_chk(void*, int, unsigned int, unsigned int) will always overflow destination buffer [enabled by default] return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest)); ^ In function ‘void* memset(void*, int, size_t)’, inlined from ‘int BFS(int)’ at user.cpp:17:33: /usr/include/i386-linux-gnu/bits/string3.h:85:70: warning: call to void* __builtin___memset_chk(void*, int, unsigned int, unsigned int) will always overflow destination buffer [enabled by default] return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest)); ^