Compilare: main.cpp: In function 'int pr1()': main.cpp:24:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<x[a].size();i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:42:29: warning: narrowing conversion of 'c' from 'int' to 'short int' inside { } [-Wnarrowing] x[a].push_back({b,c}); ^