- - - - - - - - - - - - - - - - - - - - - -Version 2.5 - Newspaper Mode Added - 8/15/81 - - - - - - - - - - - - - - - - - - - - - - - - - - - - -This forum thread is now the Support URL for this app. The Apple Store "What's New" refers to the example given here so this post and the app submission have to happen at the same time. But (hopefully) it should be only a few days before release 2.5 gets reviewed and shows up in the store.
"Newspaper Mode" option:If this new option is selected, the solutions possible in each empty cell are not given to you. Previously, without this option, you were given these solutions for all levels higher than Basic whether you wanted them or not.
This option can be set from the main Menu, since it affects just about every action in the Menu, including which puzzle you are given to solve, how puzzles are created, and how puzzles are graded.
The example below shows how you would solve a puzzle in this mode, following exactly the same steps used by the Grader. It really is a Moderate puzzle, despite its strategy rating of "Advanced" due to its one use of a Y-Wing.
Change in Moderate strategies and visual aids:Line-Block Intersections are now considered Moderate strategies. The existing visual aid that lets you highlight a particular possible solution is now available at this level.
The visual aid that highlights all cells containing a pair now lets you show only pair cells that can be seen and that have a possible in common with a selected pair cell. This makes a Y-Wing a lot easier to find.
Creation of puzzles improved:Creation is now done in batches. You are a shown the puzzle and its Grader statistics of the best of a batch while the next batch of puzzles is being created. This also seems to result in a wider variety of puzzles.
If you haven't created a pattern for creating puzzles, you will now be given a default pattern. Try this with the "No Target" option - this will produce puzzles restricted to this pattern for several different levels.
About Y-Wings and using the new visual aid:You are not likely to see a Y-Wing in a newspaper puzzle. If you are not familiar with them, the following is all you need to know:
A Y-Wing consists of 3 cells, each containing a pair of possibles (perhaps "V-Wing" would have been a better name). It is simple, but very powerful, as it creates a strong logical connection between 2 possible solutions. These possibles can't even "see" each other, and can be located anywhere in the puzzle, which is what makes Y-Wings difficult to see.
A Y-Wing looks like (c,a)--(a,b)--(b,c), where the two "a"s are connected in one unit (row, column or block) and the two "b"s are connected in another unit.
If you look at a Y-Wing as a simple chain, it has alternating strong and weak links, just like many chains do.
If you assume "c" in the first cell is not a solution, then "a" has to be a solution because pairs in a cell are strongly linked: one possible not being a solution implies the other one must be.
The unit connecting the two "a"s need only provide a weak link. No matter how many "a"s there are in that unit, the first "a" being a solution implies the next "a" in the chain is not a solution. The same is true for the "b"s and their unit.
And so forth to the other "c" at the other end of the chain, which then turns out to be a solution. The same is true traveling backwards from the "c" in the last cell to the "c" in the first cell.
And so the two "c"s are strongly linked by implication: one "c" not being a solution implies the other "c" is a solution.
And so any other "c" in the puzzle that can "see" (is in the same unit as) both of these linked "c"s can be removed, as it no longer is a possible solution.
A Y-Wing is a natural for Newspaper Mode, since you don't need to know any other possibles other than the 3 cell possible pairs and the target possible.
The "Show Pairs" visual aid makes Y-Wings more visible. Selecting the middle (a,b) cell will highlight only pair-cells containing "a" or "b" in units containing (a,b).
You do need to ignore the common case where all 3 cells are in the same unit. This would be a naked triple and should be looked at as one, and most likely has already been looked at.
If you used Create in NewsPaper Mode to create a bunch of Advanced one-star puzzles, many of them would contain a Y-Wing.
- - - - - - - - - - - - - - - - - - - - - - - - - Newspaper Mode Example - - - - - - - - - - - - - - - - - - - - - - - - - - - At the top of the Menu screen below, you will see an option to select Newspaper Mode or not. This new option can be selected here since it affects all the actions in the menu. "Newspaper mode" means that the solutions possible in each empty cell are not given to you - something that use to be true only at the Basic level, but now is available as an option for all levels.
In Newspaper mode, you will find that you go about solving puzzles in a different way, and many find this way more enjoyable. Many really don't want a computer to partially solve the puzzle for them, and then have to look at 50 to 60 cells filled with possible solutions, which either may not be all that helpful, or may be too helpful
The visual aids remain the same, except that "Show Pairs" has been enhanced as shown in the last screenshot. This enhancement makes finding Y-Wings and some other chains a lot easier.
- Menu and Input puzzle loaded
- menu + input.png (109.32 KiB) Viewed 2233 times
The following screenshots were made while solving this puzzle following the same steps used by the Grader (which solves a puzzle in the way it assumes a human would solve it).
The first time you select a puzzle from the release 2.5 "Advanced" library, indicate one "star" and you will get the puzzle shown below. You can then also follow the steps used by the Grader.
The Grader solves puzzles in a different way when Newspaper Mode is active. It keeps track of the possibles that might be noted by a user solving the puzzle, and applies strategies based only on what the user sees, just as the user would.
The possibles shown below are all these possibles. At the Basic level, you might not make notes of all of them as the Grader does here. At this level, only units with 2 or 3 empty cells have their cells filled in order to find "easy" singles.
- Basic, Moderate and Advanced levels
- basic + moderate + advanced.png (247.3 KiB) Viewed 2233 times
Basic Level:The screenshot on the left shows the situation after the Grader realizes it can't solve the puzzle at the Basic level. The Grader got to this point by finding just block unit singles - it wasn't necessary to look for the more difficult to see row or column singles.
Only units having 2 or 3 empty cells were filled with possibles in order to find "easy" singles. What you see here are the possibles left over after almost 11 singles were found that way
Moderate Level:At the Moderate level, the Grader first looked for naked pairs, triples and quads, but found none that eliminated possibles. The one naked pair (noted as "np:1" in the Grader statistics) was found after the Y-Wing was found. But it did find 4 line-block intersections (noted as "int:4").
If you look at the Fundamentals topic titled "Line-Block Intersection", you will see "Pointing Pair" and "Box-Line Reduction" in the subtitle, which may be more familiar to you. But it is the property of the 3-cell intersection, where a line (row or column) crosses a block that is behind both of these strategies.
If you tap "Selected Possible" and then tap possible "9" in the keypad, you will circle all "9"s. In this case we get to see examples of both the above strategies.
In the top left block, you will see two 9's in the intersection with row 1, and none elsewhere in the block. This means that the solution must be in the intersection, and so the other 9 in row 1 can be deleted. You can delete it without getting out of "Select Possible" mode, since 9 is the selected possible and so tapping it in the keypad acts normally.
This is an example of a "Pointing Pair", and it often is a pair but it doesn't have to be one.
When the Grader sees a possible in more than one 3-cell intersection in a block, it sees if it can find the intersection where the possible doesn't show up elsewhere in the intersecting row or column. This is the case in the block below, where column 3 intersects with the block. In this case the two other 9's in the block can be deleted.
The only difference between "Pointing Pair" and "Box-Line Reduction" is whether the block or line determine that the solution is in the intersection. Once that is determined, all other possible instances outside the intersection in either unit can be deleted since the intersection is part of both units.
For similar reasons, the top row 3's in the top left block can be removed, and the leftmost 6 in row 6 can be removed.
If a puzzle is not solved at the Moderate level, it is likely that all possibles will be filled. At this level, the Grader adds possibles where they look useful, such as when a naked multiple already exists in a unit, but some cells are still empty.
But the number of possibles that you have to deal with is minimal compared to non-newspaper mode.
Advanced LevelAt this level, you will find the "Show Pairs" visual aid useful as well as "Selected Possible". "Show Pairs" colors the background of all cells containg a pair of possibles.
In this release this aid has been improved as follows: when you select a cell containg a pair from all the shown pairs, only those cells in units to which the selected cell belongs that contain exactly one of the selected cell's possibles are colored.
In looking for a Y-Wing, you would select a pair cell as the possible "middle" cell of a Y-Wing, for instance the (6,9) cell shown. (We borrowed the Draw mode from the Extreme toolkit just to show you the Y-Wing, not that it was at all necessary to draw it.)
You can see that there is a (6,5) and a (6,3) as possible end cells, but only (6,5) has a corresponding (9,5) as the other end of the Y-Wing.
So 5's are the Y-Wing end-possibles. One of these 5's has to be a solution, which means that the 5 in row 3 column 1 can be removed, since it "sees" both of them.
This exposes the naked pair (3,6) in column 1, which exposes the now naked 9 in the top cell, and then it's singles to the end.
