Compilare: main.cpp: In function 'void computepre(std::__cxx11::string)': main.cpp:25:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < s.size()) { ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:46:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=s1.size(); i < s1.size() + s2.size() + 1; i++) { ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:47:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pre[i] == s1.size()) { ~~~~~~~^~~~~~~~~~~~ main.cpp:58:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < sol.size(); i++) ~~^~~~~~~~~~~~