Compilare: main.cpp: In function 'bool exista(long long 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:50:10: warning: statement has no effect [-Wunused-value] for(i; i < strlen(s); i ++) { ^ main.cpp:50:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i; i < strlen(s); i ++) { ~~^~~~~~~~~~~