Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:17:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int it = 0; it < graph[current].size(); ++it) { ~~~^~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:30:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.in", "r", stdin); ^ main.cpp:31:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out", "w", stdout); ^ main.cpp:33:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ main.cpp:36:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^