gropi.cpp: In function 'void dfs(int, int)': gropi.cpp:22: warning: comparison between signed and unsigned integer expressions gropi.cpp: In function 'int valid(int)': gropi.cpp:47: warning: comparison between signed and unsigned integer expressions gropi.cpp: In function 'int main()': gropi.cpp:93: warning: unused variable 'j' gropi.cpp:91: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result gropi.cpp:92: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result gropi.cpp:94: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result gropi.cpp:97: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result