Compilare: user.cpp: In function ‘int query(int)’: user.cpp:66:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ant+i<env.size() && t>env[ant+i].x) ^ user.cpp: In function ‘int main()’: user.cpp:86:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ls.size(); ++i) { /// Select 'lower envelope' lines ^ user.cpp:94:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<stk.size(); ++i) /// Make 'lower envelope' ^ user.cpp:73:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vmin.in", "r", stdin); ^ user.cpp:74:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vmin.out", "w", stdout); ^ user.cpp:77:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&q); ^ user.cpp:79:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^ user.cpp:99:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^