Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[x].size(); i++){ ~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:26:22: warning: unused variable ‘ok’ [-Wunused-variable] int n, m, a, b, i, ok; ^~ user.cpp:27:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &n, &m); ^ user.cpp:29:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &a, &b); ^