Compilare: user.cpp: In function ‘int main()’: user.cpp:156:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();i++) ^ user.cpp:123:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("critice.in","r",stdin); ^ user.cpp:124:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("critice.out","w",stdout); ^ user.cpp:127:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d",&n,&m); ^ user.cpp:129:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d",&x,&y); ^ user.cpp:130:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&c[x][y]); ^