Compilare: main.cpp: In function 'void dfs(int)': main.cpp:20:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < v[x].size();i++){ ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:28:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("conexidad.in", "r", stdin); ^ main.cpp:29:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("conexidad.out", "w", stdout); ^ main.cpp:31:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:44:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^