Compilare: user.cpp: In function ‘void precompute()’: user.cpp:18:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < s1.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:44:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < s2.size()) { ^ user.cpp:48:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == s1.size()) { ^