Compilare: main.cpp: In function 'bool exista(int)': main.cpp:16:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < h[k].size(); i ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:50:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < strlen(s)) { ~~^~~~~~~~~~~