D:题意:树上每个顶点有个权值,求最长链,满足链上gcd > 1 解:对每个质数建虚树,每个点只会拆成log个点,所以是log2的. #include <bits/stdc++.h> ; struct Edge { int nex, v, len; }edge[N << ], EDGE[N << ]; int tp, TP; ][], pw[N << ], n, ans, id[N], last[N]; int vis[N]; int imp[N],…