Compilare: user.cpp: In function ‘int main()’: user.cpp:78:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrsec.in","r",stdin); ^ user.cpp:79:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrsec.out","w",stdout); ^ user.cpp:81:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%lld",&N,&K); ^ user.cpp:85:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld",&s[i].first); ^ user.cpp: In function ‘long long int search()’: user.cpp:74:12: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized] return ret; ^