Compilare: main.cpp: In function 'void dfs_in(int, int)': main.cpp:34:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < in1[x].size(); ++i) { ~~^~~~~~~~~~~~~~~ main.cpp: In function 'void dfs_out(int, int, int, Data)': main.cpp:51:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[x].size(); ++i) { ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:58:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("plimbare3.in", "r", stdin); ^ main.cpp:59:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("plimbare3.out", "w", stdout); ^ main.cpp:60:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:63:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &u, &v); ^