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The Puzzle |
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| Introduction
The puzzle The algorithm Program Design
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Overview: The "15-puzzle" is a
common children's toy. It consists of a square container. In this
container, are placed 15 smaller square blocks. The length of each block
is about 1/4th the length of the container. So, the container can
accommodate 4 rows of 4 blocks each (16 blocks in all).
The game comes with 15 blocks. These are numbered 1,2,3...and so on. The 16th place is left free. It looks something like this:
The objective is to slide the blocks, one at a time until one has all the blocks organized in some fashion. For instance, a common goal is to try to organize the blocks so that the numbers are in ascending order, row by row, top to bottom. |
The Goal:  .
How would one get from the "shuffled" state to the goal state? Playing: Look at the shuffled state in the picture to the left. There are three possible moves:
One might move the "5" down, then one might move the "1" to the left, so that it occupies top-left position, where you want it to be. Then, similarly, one might move the "2" to its final position, and so on. |
There are many variations to the puzzle. Some have a picture on them, much like a jigsaw puzzle. Other goal states may be attempted. However, certain goal states cannot be achieved from certain starting points. |
