Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:17:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g[u].size(); i++) ~~^~~~~~~~~~~~~ user.cpp:17:5: warning: this ‘for’ clause does not guard... [-Wmisleading-indentation] for(int i = 0; i < g[u].size(); i++) ^~~ user.cpp:19:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘for’ s.push(u); ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:26:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < gt[u].size(); i++) ~~^~~~~~~~~~~~~~ user.cpp:26:5: warning: this ‘for’ clause does not guard... [-Wmisleading-indentation] for(int i = 0; i < gt[u].size(); i++) ^~~ user.cpp:28:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘for’ aux.push_back(u); ^~~ user.cpp: In function ‘int main()’: user.cpp:50:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ans.size(); i++) ~~^~~~~~~~~~~~ user.cpp:53:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < ans[i].size(); j++) printf("%d ", ans[i][j]); ~~^~~~~~~~~~~~~~~ user.cpp:33:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in", "r", stdin); ^ user.cpp:34:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out", "w", stdout); ^ user.cpp:36:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:39:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^