Compilare: main.cpp: In function 'bool isGood(long int)': main.cpp:49:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<O.size()-1;i++){ ~^~~~~~~~~~~ main.cpp:50:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i+1;j<O.size();j++){ ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:67:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("segmente.in","r",stdin); ^ main.cpp:68:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("segmente.out","w",stdout); ^ main.cpp:70:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&n); ^ main.cpp:72:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld %ld %ld",&x1,&y1,&x2,&y2); ^