[中譯] Puzzleup 2012 (1) Fifty Coins
看板puzzle (益智遊戲 - 數獨,拼圖,推理,西洋棋)作者LPH66 (杇瑣)時間12年前 (2012/07/25 19:08)推噓25(25推 0噓 39→)留言64則, 13人參與討論串1/1
題目網址: www.puzzleup.com/2012/puzzle/?240
加分時限: 7/26 7PM - 8/2 7PM
答對可得基本分100分。答案可上傳5次,每改1次答案從基本分扣20分。
比賽期間內可隨時上傳答案,加分時限內答對第n天加(6-n)分
另依題目的難易有額外加分(如有80%的人這題答錯,答對者加80分)
◆Fifty Coins
There are 50 coins. Half of them are genuine and the other half are
counterfeit. Genuine coins weigh 10 grams, while counterfeit coins differ
from the genuine coins by 1 gram (some of them weigh 9 grams, and some of
them weigh 11 grams). You have a balance scale with two pans. In each
weighing the scale shows the difference of the weights placed in each pan.
You will randomly choose a coin. What is the minimum number of weighings
necessary to guarantee to determine whether it is genuine or not?
Notes:
*You can't use the chosen coin in the weighing processes.
*You must place at least one coin to each pan.
*The scale displays only the difference of the weights as a non-negative
number. It doesn't give any information that which side is heavier.
這裡有五十枚硬幣,有一半是真幣,一半是假幣。
真幣每個重十克,而假幣則和真幣差一克(有些是九克,有些是十一克)。
現在有個天平,每次秤時可以顯示兩個秤盤上的重量差。
若隨機選擇一個硬幣,問至少要秤幾次才能確定這幣是真幣還假幣?
註:
*你不能將所選的硬幣放上秤。
*每次上秤至少兩盤要各放一個硬幣。
*天平只會告訴你兩盤的重量差而不會說哪邊比較重。
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第一題就來這招啊...
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※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.112.28.91
推
07/25 19:11, , 1F
07/25 19:11, 1F
→
07/25 19:12, , 2F
07/25 19:12, 2F
推
07/25 19:25, , 3F
07/25 19:25, 3F
推
07/25 19:25, , 4F
07/25 19:25, 4F
→
07/25 19:25, , 5F
07/25 19:25, 5F
→
07/25 19:25, , 6F
07/25 19:25, 6F
→
07/25 19:26, , 7F
07/25 19:26, 7F
→
07/25 19:29, , 8F
07/25 19:29, 8F
推
07/25 19:32, , 9F
07/25 19:32, 9F
推
07/25 19:38, , 10F
07/25 19:38, 10F
推
07/25 19:41, , 11F
07/25 19:41, 11F
→
07/25 19:41, , 12F
07/25 19:41, 12F
→
07/25 19:42, , 13F
07/25 19:42, 13F
→
07/25 19:42, , 14F
07/25 19:42, 14F
→
07/25 20:01, , 15F
07/25 20:01, 15F
→
07/25 20:01, , 16F
07/25 20:01, 16F
→
07/25 20:03, , 17F
07/25 20:03, 17F
推
07/25 20:31, , 18F
07/25 20:31, 18F
→
07/25 20:57, , 19F
07/25 20:57, 19F
推
07/25 21:40, , 20F
07/25 21:40, 20F
推
07/25 21:45, , 21F
07/25 21:45, 21F
好, 題目加了一個不得了的限制...
這下這題目有趣了 XD
※ 編輯: LPH66 來自: 140.112.28.91 (07/25 22:42)
推
07/25 22:47, , 22F
07/25 22:47, 22F
推
07/25 22:53, , 23F
07/25 22:53, 23F
→
07/25 22:53, , 24F
07/25 22:53, 24F
推
07/25 23:04, , 25F
07/25 23:04, 25F
→
07/25 23:05, , 26F
07/25 23:05, 26F
→
07/25 23:05, , 27F
07/25 23:05, 27F
推
07/25 23:10, , 28F
07/25 23:10, 28F
→
07/25 23:10, , 29F
07/25 23:10, 29F
推
07/26 00:15, , 30F
07/26 00:15, 30F
推
07/26 00:26, , 31F
07/26 00:26, 31F
→
07/26 06:03, , 32F
07/26 06:03, 32F
→
07/26 06:05, , 33F
07/26 06:05, 33F
→
07/26 11:52, , 34F
07/26 11:52, 34F
→
07/26 12:03, , 35F
07/26 12:03, 35F
推
07/26 13:19, , 36F
07/26 13:19, 36F
→
07/26 13:19, , 37F
07/26 13:19, 37F
→
07/26 13:20, , 38F
07/26 13:20, 38F
推
07/26 14:18, , 39F
07/26 14:18, 39F
→
07/26 14:51, , 40F
07/26 14:51, 40F
→
07/26 14:53, , 41F
07/26 14:53, 41F
→
07/26 14:54, , 42F
07/26 14:54, 42F
→
07/26 14:55, , 43F
07/26 14:55, 43F
推
07/26 15:13, , 44F
07/26 15:13, 44F
→
07/26 15:14, , 45F
07/26 15:14, 45F
→
07/26 15:32, , 46F
07/26 15:32, 46F
又有條件新增了
這最後一個條件...@@
※ 編輯: LPH66 來自: 140.112.28.91 (07/26 17:30)
推
07/26 17:48, , 47F
07/26 17:48, 47F
推
07/26 18:24, , 48F
07/26 18:24, 48F
推
07/26 18:32, , 49F
07/26 18:32, 49F
→
07/26 18:32, , 50F
07/26 18:32, 50F
→
07/26 18:34, , 51F
07/26 18:34, 51F
→
07/26 18:41, , 52F
07/26 18:41, 52F
推
07/26 19:06, , 53F
07/26 19:06, 53F
→
07/26 19:07, , 54F
07/26 19:07, 54F
→
07/26 19:08, , 55F
07/26 19:08, 55F
推
07/26 19:08, , 56F
07/26 19:08, 56F
推
07/26 19:14, , 57F
07/26 19:14, 57F
→
07/26 21:13, , 58F
07/26 21:13, 58F
→
07/26 21:14, , 59F
07/26 21:14, 59F
→
07/26 21:15, , 60F
07/26 21:15, 60F
→
07/26 21:16, , 61F
07/26 21:16, 61F
→
07/26 21:16, , 62F
07/26 21:16, 62F
推
07/26 21:51, , 63F
07/26 21:51, 63F
→
07/26 21:52, , 64F
07/26 21:52, 64F
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