virgule.cpp: In function 'void solve(int, int, int, int)': virgule.cpp:97: warning: comparison between signed and unsigned integer expressions virgule.cpp: In function 'int main()': virgule.cpp:109: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result virgule.cpp:110: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result