Compilare: main.cpp: In function 'long long unsigned int C(long long unsigned int, long long unsigned int)': main.cpp:8:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=n;i>n-k;--i) ~^~~~ main.cpp:10:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=k;++i) ~^~~ main.cpp: In function 'int main()': main.cpp:17:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=N;++i) ~^~~ main.cpp:18:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1;j<=i && j<=K;++j) ~^~~