Compilare: user.cpp: In function ‘int main()’: user.cpp:263:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vaporeon.in", "r", stdin); ^ user.cpp:264:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vaporeon.out", "w", stdout); ^ user.cpp: In function ‘void Swap(int)’: user.cpp:159:9: warning: ‘L’ may be used uninitialized in this function [-Wmaybe-uninitialized] int L, R; ^ user.cpp:28:14: warning: ‘R’ may be used uninitialized in this function [-Wmaybe-uninitialized] for(i=y+1; i<=n; i+=ub(i)) a[i] += y * add, b[i] -= add; ~^~~~ user.cpp:159:12: note: ‘R’ was declared here int L, R; ^