Compilare: user.cpp: In function ‘int main()’: user.cpp:33:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[dad].size(); i++) ^ user.cpp:44:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[x].size(); i++) ^ user.cpp:11:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.in", "r", stdin); ^ user.cpp:12:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.out", "w", stdout); ^ user.cpp:15:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &n, &m, &u, &x); ^ user.cpp:18:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a); ^ user.cpp:25:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &a, &b); ^