Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:35:43: warning: operation on ‘di’ may be undefined [-Wsequence-point] d[++di] = d[ di - v[*it] ] + 1; ^ user.cpp: In function ‘void read()’: user.cpp:18:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:21:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^ user.cpp:23:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:57:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cerere.in", "r", stdin); ^ user.cpp:58:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cerere.out", "w", stdout); ^ user.cpp: In function ‘void solve()’: user.cpp:50:14: warning: ‘root’ may be used uninitialized in this function [-Wmaybe-uninitialized] dfs(root); ^