Compilare: user.cpp: In function ‘void solve()’: user.cpp:19:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(sir[k]!=')' && k<strlen(sir)) ^ user.cpp: In function ‘int main()’: user.cpp:49:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(k<strlen(sir)) ^ user.cpp:54:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] { for(int j=0;j<s[i].size();j++) ^