[其他] 離散一題
題目: https://imgur.com/a/oCMXgxw
不知道想法對不對
(a)
Since if n has k digits, then the shortest-length formula must be <= k.
-> shortest-length formula must be finite
It's possible to enumerate the set of possible arithmetic formulas for n,
with condition len(each formula) <= k
-> the set is finite
-> We can find the shortest-length formula in that set for a given n.
-> It's possible to write a program to find the shortest formula for any n.
(b)
先說hint部分
我不太知道要如何判斷
a program halts on given input -> halting problem -> unsolvable
多了within t steps
我應該可以用個counter去數有沒有超過t
所以應該做得出來
還有如果a program does not halt within t steps
execution time就找不到minimum吧
那整個program cannot be done
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 61.224.180.237 (臺灣)
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1603792548.A.D7B.html
→
10/27 22:07,
3年前
, 1F
10/27 22:07, 1F
→
10/27 22:08,
3年前
, 2F
10/27 22:08, 2F
→
10/27 22:08,
3年前
, 3F
10/27 22:08, 3F
→
10/27 22:09,
3年前
, 4F
10/27 22:09, 4F
→
10/27 22:09,
3年前
, 5F
10/27 22:09, 5F
→
10/27 22:09,
3年前
, 6F
10/27 22:09, 6F
→
10/27 22:10,
3年前
, 7F
10/27 22:10, 7F
→
10/27 22:10,
3年前
, 8F
10/27 22:10, 8F
→
10/27 22:10,
3年前
, 9F
10/27 22:10, 9F
→
10/27 22:11,
3年前
, 10F
10/27 22:11, 10F
→
10/27 22:11,
3年前
, 11F
10/27 22:11, 11F
→
10/27 22:12,
3年前
, 12F
10/27 22:12, 12F
→
10/27 22:15,
3年前
, 13F
10/27 22:15, 13F
→
10/27 22:15,
3年前
, 14F
10/27 22:15, 14F
→
10/27 23:01,
3年前
, 15F
10/27 23:01, 15F
→
10/27 23:02,
3年前
, 16F
10/27 23:02, 16F
→
10/27 23:04,
3年前
, 17F
10/27 23:04, 17F
→
10/27 23:04,
3年前
, 18F
10/27 23:04, 18F
→
10/27 23:06,
3年前
, 19F
10/27 23:06, 19F
→
10/27 23:06,
3年前
, 20F
10/27 23:06, 20F
→
10/27 23:07,
3年前
, 21F
10/27 23:07, 21F
→
10/27 23:08,
3年前
, 22F
10/27 23:08, 22F
→
10/27 23:10,
3年前
, 23F
10/27 23:10, 23F
→
10/27 23:12,
3年前
, 24F
10/27 23:12, 24F
→
10/27 23:13,
3年前
, 25F
10/27 23:13, 25F
→
10/27 23:15,
3年前
, 26F
10/27 23:15, 26F
→
10/27 23:15,
3年前
, 27F
10/27 23:15, 27F
→
10/27 23:27,
3年前
, 28F
10/27 23:27, 28F
→
10/27 23:28,
3年前
, 29F
10/27 23:28, 29F
討論串 (同標題文章)