net.cpp: In function 'int main()':
net.cpp:30:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < order.size(); ++i)
^
net.cpp:18:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
freopen("a.in", "r", stdin);
^
net.cpp:19:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
freopen("a.out", "w", stdout);
^
net.cpp:21:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
int n; scanf("%d", &n);
^
net.cpp:24:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
int u, v; scanf("%d %d", &u, &v);
^