Compilare: user.cpp: In function ‘int solve(const string&, const string&)’: user.cpp:111:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ( i < x.size() && j < y.size() && x[i] == y[j] ) i++, j++, c++; ^ user.cpp:111:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ( i < x.size() && j < y.size() && x[i] == y[j] ) i++, j++, c++; ^ user.cpp:99:9: warning: unused variable ‘sol’ [-Wunused-variable] int sol = 0; ^ user.cpp: In function ‘int main()’: user.cpp:122:18: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] FIN("zip.in"); ^ user.cpp:123:20: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] FOUT("zip.out"); ^