diff options
Diffstat (limited to 'prolog/problems/denotational_semantics/prog_8puzzle_3')
| -rw-r--r-- | prolog/problems/denotational_semantics/prog_8puzzle_3/common.py | 4 | ||||
| -rw-r--r-- | prolog/problems/denotational_semantics/prog_8puzzle_3/en.py | 31 |
2 files changed, 28 insertions, 7 deletions
diff --git a/prolog/problems/denotational_semantics/prog_8puzzle_3/common.py b/prolog/problems/denotational_semantics/prog_8puzzle_3/common.py index 13debcf..0e0d048 100644 --- a/prolog/problems/denotational_semantics/prog_8puzzle_3/common.py +++ b/prolog/problems/denotational_semantics/prog_8puzzle_3/common.py @@ -1,6 +1,6 @@ id = 173 -number = 82 -visible = False +number = 40 +visible = True facts = 'denotational_semantics_aux__predicates' solution = '''\ diff --git a/prolog/problems/denotational_semantics/prog_8puzzle_3/en.py b/prolog/problems/denotational_semantics/prog_8puzzle_3/en.py index 51aa81a..7a94c74 100644 --- a/prolog/problems/denotational_semantics/prog_8puzzle_3/en.py +++ b/prolog/problems/denotational_semantics/prog_8puzzle_3/en.py @@ -2,17 +2,38 @@ name = 'prog_8puzzle/3' slug = '8-puzzle-solving language with semantics' description = '''\ -<p>Write a DCG for solving 8-puzzles. The syntax for this language should be the same as in the previous exercise: the first symbol in every word is <code>[begin]</code>, followed by any sequence of "instruction" symbols from the set {<code>left</code>, <code>right</code>, <code>up</code>, <code>down</code>}, and finally <code>[end]</code>. The starting symbol should be named <code>prog_8puzzle</code>.</p> +<p> +Write a DCG for solving 8-puzzles. The syntax for this language should be the +same as in the previous exercise: the first symbol in every word is +<code>[begin]</code>, followed by any sequence of "instruction" symbols from +the set {<code>left</code>, <code>right</code>, <code>up</code>, +<code>down</code>}, and finally <code>[end]</code>. The starting symbol should +be named <code>prog_8puzzle</code>. +</p> -<p>The meaning of a word (program) in this language has the form <code>In-->Out</code>, mapping from input to output states. Each state is a (permuted) list of numbers from 0 to 8, where 0 stands for the empty square and other numbers for the corresponding tiles. The first three numbers in the list correspond to the top row of the 8-puzzle, the next three numbers to the middle row, and the last three numbers to the last row. The meaning of instructions <code>left</code>, <code>right</code>, <code>up</code> and <code>down</code> is to move the blank tile in the given direction.</p> +<p> +The meaning of a word (program) in this language has the form +<code>In-->Out</code>, mapping from input to output states. Each state is a +(permuted) list of numbers from 0 to 8, where 0 stands for the empty square and +other numbers for the corresponding tiles. The first three numbers in the list +correspond to the top row of the 8-puzzle, the next three numbers to the middle +row, and the last three numbers to the last row. The meaning of instructions +<code>left</code>, <code>right</code>, <code>up</code> and <code>down</code> is +to move the blank tile in the given direction. +</p> <pre> ?- prog_8puzzle([0,1,2,3,4,5,6,7,8]-->Out, [begin,down,right,end], []). Out = [3,1,2,4,0,5,6,7,8]. </pre> -<p>Helper predicates (already defined):<br /> - <code>findblank(List,I)</code> returns the 1-based index <code>I</code> of the element 0 in <code>List</code><br /> - <code>swap(List,I,J,NewList)</code> creates <code>NewList</code> by swapping elements <code>I</code> and <code>J</code> in <code>List</code></p>''' +<p> +Helper predicates (already defined): +</p> +<ul> +<li><code>findblank(List,I)</code> returns the 1-based index <code>I</code> of the element 0 in <code>List</code></li> +<li><code>swap(List,I,J,NewList)</code> creates <code>NewList</code> by swapping elements <code>I</code> and <code>J</code> in <code>List</code></li> +</ul> +''' hint = {} |