Compilare: user.cpp: In function ‘void expand()’: user.cpp:9:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] void expand(){while(r+1<b.size()&&b[r+1]==b[r-l+1])++r;} ^ user.cpp: In function ‘void expand2()’: user.cpp:10:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] void expand2(){while(r+1<c.size()&&c[r+1]==c[r-l+1])++r;} ^ user.cpp: In function ‘int main()’: user.cpp:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1;i<b.size();++i){ ^ user.cpp:48:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1;i<c.size();++i){ ^ user.cpp:69:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=n;i<b.size();++i) ^