Compilare: user.cpp: In function ‘void solve()’: user.cpp:89:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<mag.size();i++){ ^ user.cpp: In function ‘int main()’: user.cpp:113:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("magnet.in","r",stdin); ^ user.cpp:114:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("magnet.out","w",stdout); ^ user.cpp:117:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&t); ^ user.cpp:119:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&n); ^ user.cpp:121:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&A[i]); ^ user.cpp:123:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&B[i]); ^