Compilare: user.cpp: In function ‘int main()’: user.cpp:15:26: warning: unused variable ‘first’ [-Wunused-variable] int i,j,N,K,idx,temp,first; ^ user.cpp:12:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cuburi5.in","r",stdin); ^ user.cpp:13:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cuburi5.out","w",stdout); ^ user.cpp:17:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&N,&K); ^ user.cpp:22:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i][j]); ^ user.cpp:56:23: warning: ‘idx’ may be used uninitialized in this function [-Wmaybe-uninitialized] idx = fiu[idx]; ^