传送门 Description Let S be a number string, and occ(S,x) means the times that number x occurs in S. i.e. S=(1,2,2,1,3),occ(S,1)=2,occ(S,2)=2,occ(S,3)=1. String u,w are matched if for each number i, occ(u,i)=occ(w,i) always holds. i.e. (1,2,2,1,3)≍(1,3,…