[問題] DAG找最短路徑問題

看板Prob_Solve (計算數學 Problem Solving)作者 (StarNighT)時間11年前 (2013/02/03 18:30), 編輯推噓1(105)
留言6則, 3人參與, 最新討論串1/1
最近友人問我一個演算法的考題 找了很多資料還是不太會想請教大大們 Let G be a direct acyclic graph with vertex set V and arc set E. Suppose that s is the only vertwx with in-degree zero. Consider following for finding the shorest path lengths from s to all the other vertices. Here each arc has unit length. Algorithm TTT find a (__) (v1=s,v2,...,vn) of G // What kind of sequence it is set d[1]=0 and d[i]=n for any i>1; for i from 1 to n-1 do for each j such that there is an arc (vi,vj) do if (__) then (__) the time complexity is O(__) 問這4個填空 我只有找到是最後一個好像是O(|V|+|E|) 不知道可不可以在這問,如果不行我會刪除 感謝! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 1.168.102.152 ※ 編輯: VeranoDB 來自: 1.168.102.152 (02/03 18:31)

02/03 20:32, , 1F
第一個空格應該跟拓樸順序有關
02/03 20:32, 1F

02/03 20:32, , 2F
第二, 三個空格就是 relax, 比較短就放鬆
02/03 20:32, 2F

02/03 23:08, , 3F
topological sorted order, d[vi]+arc(vi,vj) <d[vj]
02/03 23:08, 3F

02/03 23:08, , 4F
d[vj] = d[vi] + arc(vi,vj)
02/03 23:08, 4F

02/03 23:08, , 5F
猜的
02/03 23:08, 5F

02/07 00:15, , 6F
感謝回答
02/07 00:15, 6F
文章代碼(AID): #1H3ZmnAp (Prob_Solve)
文章代碼(AID): #1H3ZmnAp (Prob_Solve)