Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[v].size(); i ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:167:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("trampoline.in", "r", stdin); ^ main.cpp:168:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("trampoline.out", "w", stdout); ^