Compilare: main.cpp: In function 'long long int recurs(int, int)': main.cpp:13:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (long long i=0; i<q.size(); i++) ~^~~~~~~~~ main.cpp:44:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (long long i=0; i<q.size(); i++) ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:82:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (long long i=1; i<=n; i++) ~^~~ main.cpp:83:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (long long j=1; j<=n; j++) ~^~~ main.cpp:84:45: warning: NULL used in arithmetic [-Wpointer-arith] if (a[i][j]==0&&c[i][j][0]!=NULL) ^~~~