Compilare: main.cpp: In function 'int main()': main.cpp:23:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0,cnt;i<v[0].size();++i){ ~^~~~~~~~~~~~ main.cpp:25:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i+1<v[0].size() && v[0][i]==v[0][i+1]) ++i; ~~~^~~~~~~~~~~~ main.cpp:28:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p[j] < v[j].size() && v[j][p[j]] < v[0][i]) ++p[j]; ~~~~~^~~~~~~~~~~~~ main.cpp:29:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p[j] < v[j].size() && v[j][p[j]] == v[0][i]) ~~~~~^~~~~~~~~~~~~