[理工] [資結]-師大93-資教

看板Grad-ProbAsk作者 (IDontBite)時間16年前 (2010/01/27 17:18), 編輯推噓2(2推 0噓 2→)
留言4則, 3人參與, 最新討論串1/1
Suppose that we have a file in which each record has 3 component keys (k1,k2,k3). To sort these into lexicographic order, we decide to sort the entire file by k3, then sort the entire file by k2, and finally sort the entire file by k1. For this to work correctly, which sorts must be done by stable sorting algorithms? (A) The sort by k3 (B) The sort by k2 (C) The sort by k1 (D) Both (A) and (B) (E) Both (B) and (C) 答案給D, 但我覺得是E (C不stable那前面都在排心酸的), 大家覺得? -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.32.189.59
推
01/27 17:24, , 1F
我也覺得是E
01/27 17:24, 1F
推
01/28 17:11, , 2F
排的順序是k3→k2→k1，k3跟k2要stable，D應該沒錯吧
01/28 17:11, 2F
→
01/28 17:54, , 3F
排(3,0,5),(3,1,5),(3,2,5),(3,3,5),k1那次用heapsort
01/28 17:54, 3F
→
01/28 17:56, , 4F
排出來會是(3,1,5),(3,2,5),(3,3,5),(3,0,5)
01/28 17:56, 4F
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