Compilare: user.cpp: In function ‘void solve(std::vector<int>)’: user.cpp:57:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans>A.size()/2) ^ user.cpp: In function ‘int main()’: user.cpp:150:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("egal.in","r",stdin); ^ user.cpp:151:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("egal.out","w",stdout); ^ user.cpp:153:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:157:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&X,&Y); ^ user.cpp:162:12: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^ user.cpp:163:10: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ /tmp/ccCTDB2A.o: In function `main': user.cpp:(.text.startup+0x124): warning: the `gets' function is dangerous and should not be used.