Compilare: main.cpp: In function 'void solve()': main.cpp:20:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(a);i++) ~^~~~~~~~~~ main.cpp:26:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(a);i++) ~^~~~~~~~~~ main.cpp:35:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=strlen(a);i<strlen(b);i++) ~^~~~~~~~~~ main.cpp:45:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();i++) ~^~~~~~~~~~~