Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:34:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:117:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j+1 < T[i].size(); ++j) ^ user.cpp:122:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < T[i].size(); ++j) ^ user.cpp:138:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < flights.size(); ++i) ^ user.cpp:160:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < topo.size(); ++i) ^ user.cpp:164:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[x].size(); ++j) ^ user.cpp:87:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("avioane2.in", "r", stdin); ^ user.cpp:88:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("avioane2.out", "w", stdout); ^ user.cpp:90:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(s, maxlen, 1, stdin); ^