Compilare: user.cpp: In function ‘void bfs()’: user.cpp:18:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < graf[curr].size(); ++i) { ^ user.cpp: In function ‘void solve()’: user.cpp:49:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(; index < tati[curr].size(); ++index) { ^ user.cpp: In function ‘int main()’: user.cpp:61:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.in", "r", stdin); ^ user.cpp:62:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.out", "w", stdout); ^ user.cpp:66:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &first, &last); ^ user.cpp:68:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^