Compilare: main.cpp: In function 'int main()': main.cpp:17:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= n; ++ i) ~~^~~~ main.cpp:27:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= k - 2; ++ i) ~~^~~~~~~~ main.cpp:38:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= n; ++ i) ~~^~~~ main.cpp:59:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= k && a + b < 2000000; ++ i) ~~^~~~