Compilare: user.cpp: In function ‘void Prim()’: user.cpp:25:9: warning: variable ‘ke’ set but not used [-Wunused-but-set-variable] int ke, u, v, w; ^ user.cpp: In function ‘int main()’: user.cpp:54:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in", "r", stdin); ^ user.cpp:55:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out", "w", stdout); ^ user.cpp:59:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:66:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] G[b].pb(mp(a, c)); ^