Compilare: user.cpp: In function ‘void build()’: user.cpp:75:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < nodes[i].size(); ++ j) ^ user.cpp: In function ‘int main()’: user.cpp:228:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("neapuiu.in", "r", stdin); ^ user.cpp:229:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("neapuiu.out", "w", stdout); ^ user.cpp:231:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &n, &m); ^ user.cpp:234:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &a, &b); ^ user.cpp:242:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &type[i]); ^ user.cpp:245:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &x[i], &y[i]); ^ user.cpp:251:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &x[i]); ^