Compilare: user.cpp: In function ‘int back(int, int, int, int, int)’: user.cpp:31:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (u==Size.size()) { T[d].push_back(ll); return 1; } ^ user.cpp: In function ‘std::ostream& operator<<(std::ostream&, const std::vector<int>&)’: user.cpp:40:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] f0(i,a.size()) printf(" %d", a[i]); ^ user.cpp:9:33: note: in definition of macro ‘f0’ #define f0(i,n) for (int i=0; i<n; i++) ^ user.cpp: In function ‘void execute()’: user.cpp:52:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] f0(R,Size.size()) { ^ user.cpp:9:33: note: in definition of macro ‘f0’ #define f0(i,n) for (int i=0; i<n; i++) ^ user.cpp: At global scope: user.cpp:79:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main(){ ^ user.cpp: In function ‘int main()’: user.cpp:80:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("copii.in", "r", stdin); ^ user.cpp:81:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("copii.out", "w", stdout); ^ user.cpp:82:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^