Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:38:36: warning: operation on ‘k’ may be undefined [-Wsequence-point] sum[++k] = sum[k - 1] + v[node]; ^ user.cpp: In function ‘void read()’: user.cpp:28:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &s); ^ user.cpp:30:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &v[i]); ^ user.cpp: In function ‘int main()’: user.cpp:49:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbore3.in", "r", stdin); ^ user.cpp:50:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbore3.out", "w", stdout); ^