Compilare: user.cpp: In function ‘void Mul(std::vector<std::vector<int> >&, std::vector<std::vector<int> >&)’: user.cpp:9:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < A.size(); i ++ ) { ^ user.cpp:10:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < A.size(); j ++ ) { ^ user.cpp:13:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int k = 0; k < A.size(); k ++ ) ^ user.cpp:17:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < A.size(); i ++ ) ^ user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < A.size(); j ++ ) ^ user.cpp: In function ‘void SolveTestCase()’: user.cpp:27:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d %d %d", &T, &N, &K ); ^ user.cpp: In function ‘int main()’: user.cpp:77:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "2sah.in" , "r", stdin ); ^ user.cpp:78:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "2sah.out", "w", stdout ); ^