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- PC-Sherlock - Examples of logical analysis:
- -------------------------------------------
-
- It's very interesting to know that there's no simple formula for
- winning in this logical game. Although, I am showing you a few
- example games to show how I arrived at my guesses, please don't try
- to look for a definite pattern in my play. The games generated are
- random and each game requires original thinking.
-
- You must have already seen the topic "Examples of deduction" in the
- online tutorial. If not, please read the online tutorial before
- looking at these examples. Here, I'm showing examples of 3, 4 and 5
- digit games. Note that 3 and 5 digit games are available only in the
- registered version. It's my opinion that the 3 digit game is the
- easiest to play.
-
-
- EXAMPLE 1: (3 digit game)
- =========================
- CHANCE 1: Asked 123, got 0 bull, 1 cows
- CHANCE 2: Asked 456, got 1 bulls, 1 cows
-
- Initial assumption:
- Assume that '4' is the bull, '6' and '2' are cows.
-
- CHANCE 3: Asked 462, got 0 bulls, 2 cows
-
- Deduction starts:
- Chances of '4' and '6' being present are greater than '2' being
- present. So we change the position of '4' and '6' and ask another
- digit from chance 1.
-
- CHANCE 4: Asked 346, got 3 bulls
-
- WE WIN THE GAME! Of course, here it was lucky to get two of our
- assumptions right. Otherwise, it would have taken more chances.
-
-
- EXAMPLE 2: (3 digit game)
- =========================
- CHANCE 1: Asked 123, got 2 bulls, 0 cows
- CHANCE 2: Asked 456, got 0 bulls, 1 cows
-
- Initial assumption:
- Assume that '1' and '2' are the bulls and '4' is the cow.
-
- CHANCE 3: Asked 124, got 1 bull , 0 cows
-
- Deduction starts:
- Assume '1' to be the bull. Then '2' and '4' are absent. Hence, '3' is
- present and is a bull in chance '1'. So our number is 1X3 where X is
- either '5' or '6' from chance 2. Now, X can't be '5' as the clue for
- chance 2 is 1 cow. Hence, X is '6'. So the number to ask is 163.
-
- CHANCE 4: Asked 163, got 3 bulls
-
- WE WIN THE GAME! Note that unlike the previous example, this win can't
- be attributed to just luck. The deduction worked!
-
-
- EXAMPLE 3: (4 digit game)
- =========================
- CHANCE 1: Asked 1234, got 1 bulls, 1 cows
- CHANCE 2: Asked 5678, got 0 bulls, 2 cows
-
- Initial Assumption:
- Assume '3' to be the bull and '2', '5' and '6' to be the cows. We ask
- a guess where the cows change position whereas bull does not.
-
- CHANCE 3: Asked 6532, got 3 bulls, 0 cows
-
- Deduction starts:
- We got lucky here to get 3 bulls. Now we assume that we got '5' and
- '6' right as bulls. But we are not sure whether '3' was the bull or
- the '2' became a bull on a changed position. Let's assume that '2'
- became the bull. That means '3' is absent and the number is 65X2
- where X can be '1' or '4'. Let's assume X to be '4'. So we ask 6542.
-
- CHANCE 4: Asked 6542, got 2 bulls, 0 cows.
-
- Deduction continues:
- Our clues got reduced in number from 3 bulls to 2 bulls! So most
- probably, our basic assumption that '5' and '6' are bulls seems to be
- wrong. Only one of '5' and '6' is a bull. In that case, looking at
- chance 3, digits '3' and '2' are definitely the bulls. If we assume
- '6' to be the third bull, the number is 6X32. Now from chance 2, X
- can be '7' or '8'. Let's assume X to be '7'. So the number to ask
- is 6732.
-
- CHANCE 4: Asked 6732, got 4 bulls
-
- WE WIN THE GAME!
-
-
- EXAMPLE 4: (5 digit game)
- =========================
- CHANCE 1: Asked 12345, got 0 bulls, 1 cows
-
- Elimintation technique:
- It means only one of above 5 digits is present. Let's repeat three of
- the above digits for quicker elimination of digits.
-
- CHANCE 2: Asked 67123, got 1 bulls, 0 cows
-
- Deduction starts:
- Since total seven digits asked in first two guesses covered only 1
- clue, we deduce that remaining three digits '8','9' and '0' are
- definitely present. Also, it is more probable that the bull is from
- '1', '2' and `3' instead of from '6' and '7' as '1', '2' and '3' have
- repeated in two chances and have changed positions. We aren't sure
- which one so let's repeat '1' and '2' and ask the remaining three
- digits in other positions.
-
- CHANCE 3: Asked 80129, got 0 bulls, 3 cows
-
- Deduction continues:
- Since digits '8', '9' and '0' are definitely present as per the
- previous deduction, we conclude that '1' and '2' are absent. So, from
- chance 2, digit '6', '7' or '3' was the bull. Assume '6' to be the
- bull. In that case '1', '2' and '3' are absent and we select the next
- digit from chance 1 to be the cow which is digit '4'. Let's change
- positions of '8', '9' and '0' (all cows) and ask 69804.
-
- CHANCE 4: Asked 69804, got 3 bulls, 1 cows
-
- Deduction continues:
- This means choice of '4' was wrong in the last step. Hence, we select
- the next digit '5' from chance 1. From chance 4, let's assume '6',
- '9' and '8' to be the bulls. Hence, we ask 69850. Note that we can't
- ask '5' in the last position as it was a cow there in chance 1.
-
- CHANCE 5: Asked 69850, got 2 bulls, 3 cows
-
- Deduction continues:
- Good! We at least got all the 5 digits now. Let's shift the positions
- of three assumed cows and ask again.
-
- CHANCE 6: 69508, got 5 bulls
- WE WIN THE GAME!
-
- END OF EXAMPLES
- ==================================================================
- If you haven't registered, please register PC-Sherlock and support
- independent development. Please see the ordering instructions in the
- accompanying file ORDER.DOC.
-
- Sanjay Kanade
- (Author of PC-Sherlock)
- email: 71303.20@compuserve.com