Compilare: user.cpp: In function ‘int solve(int)’: user.cpp:62:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < topo.size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:87:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.in", "r", stdin); ^ user.cpp:88:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.out","w",stdout); ^ user.cpp:89:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:94:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:98:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &val[i]); ^ user.cpp:104:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^