Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:20:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g[nod].size(); i++){ ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:27:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] { freopen("lca.in", "r",stdin); ^ main.cpp:28:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("lca.out", "w",stdout); ^ main.cpp:30:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:32:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ main.cpp:49:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^