Compilare: user.cpp: In function ‘bool Check(std::string, std::string, int)’: user.cpp:116:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ( i1 < a.size() ) ^ user.cpp: In function ‘void Write(int, int, int)’: user.cpp:131:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s[ul].size() - up; ++i ) ^ user.cpp: In function ‘void Solve()’: user.cpp:108:30: warning: ‘u’ may be used uninitialized in this function [-Wmaybe-uninitialized] Write((1 << N) - 1, u, 0); ^ user.cpp:76:28: warning: ‘r’ may be used uninitialized in this function [-Wmaybe-uninitialized] b[i][j] = r; ^