Compilare: user.cpp: In function ‘void read()’: user.cpp:19: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:20: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result user.cpp:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve()’: user.cpp:45: warning: comparison between signed and unsigned integer expressions /tmp/ccEDZDnM.o: In function `read()': user.cpp:(.text+0x289): warning: the `gets' function is dangerous and should not be used.