Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:66:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < list[node].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:103:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < queries.size(); i++) { ^ user.cpp:76:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arb.in", "r", stdin); ^ user.cpp:77:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arb.out", "w", stdout); ^ user.cpp:79:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:80:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i = 1; i <= n; i++) scanf("%d", &cost[i]); ^ user.cpp:82:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp:89:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &q); ^ user.cpp:91:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^