An even better strategy would be to solve all grids in the first 70 minutes

Simplest strategy, not sure why others couldn't come up with this idea

Maybe some people are realistic and know their limitations :D

Is this test designed so the best solvers can finish them all within 70 minutes?

I thought originally the idea of the time expansion/points reduction concept was so more people could have the time to finish all puzzles, at least i thought that's why it was brought up at least. It just gives me a small idea of the average difficulty of all puzzles. As if it is, I might approach it with the mindset of being able to finish all puzzles(which I generally don't expect to acchieve in a sudoku contest), as i think I could finish everything with almost double the time to the fastest sudoku solvers.

Looking at the list we have 22 puzzles in all ... that amounts to roughly less than 6 minutes per puzzle. I dont think more than 3 people will be able to complete all the puzzles....

Rishi

Yeah, that's what I was thinking too, but then I don't really get the idea behind the point reduction, I guess. Because why would it be better to solve a 90 point puzzle at the 60 minute mark than at the 90 minute mark, if the test isn't designed to be finished at the 70 minute mark for the fastest solvers. That's basically why I was wondering.

Edited by Para 2011-07-14 3:20 AM

I can only speculate why this particular point structure has been chosen, but I like it. I have always believed Sudoku to be a "Single Persons Chess" where just solving is not important but strategising too. In this point structure, it would be foolish to tackle puzzles in order of appearance. A little bit of strategy would be needed as to how and in which order the puzzles would be attacked.

can any body help out for how to start the "crossnumber sudoku and number 5 still alive"?
not getting a start.

For the crossnumber sudoku, you basically just have to place all numbers in the grid first. The most obvious point to start, is the left bottom corner. The left bottom vertical number, you can relatively easily prove that only 5876 is possible there, considering the numbers that can cross and the fact no digits can repeat within nonet 7. Once you have that, you should be able to fill ou the whole crossword.

Number 5 still alive I haven't figured out yet myself.



I don't really agree but I guess that's not a discussion to have here.

I mainly was just inquiring with what solving time this test was intended for the fastest solvers (as that is normally what the test length is for), to get an idea on the difficulty and thus how to approach this test. Because I was under the impression that the time extension/point reduction system was intended so that the people who finish just behind the fastest solvers can also finish all puzzles in competition for once, just for less points. Would still appreciate an answer from someone who knows for sure.

thanks para.
actually i forget considering a sudoku rule. i considered it as solving like a crossword puzzle with few guesses but forgotten the basic rule. now i will give it another strike.
"just one cell sudoku"- how to go about it. i could just get few things in the top right corner 3 x 3. but not able to get that answer '2' . can anybody give the explanation for it.

Just one cell sudoku:
R469C7 is a hidden triple {135}. Now R1C7 is a hidden single 2. Or you could do R28C7 is a naked pair {79} for C7, now R1C7 is a naked single 2.

The Number 5 Still Alive example from WSC2 was notoriously difficult and much much much more difficult than the competition puzzle was. This, in my experience, is often the case with Vlad Portugalov puzzles where the "example" is too hard to solve. After 15 minutes, I can explain how to get just 9 sure digits and 2 labeled pairs.

My hope is that someone can give you a link to another Number 5 Still Alive type puzzle from a previous mock test. I can only quickly find the related Number X is Alive puzzle from the May Sudoku test at the moment.

There was one "number 5 still alive" on fed-sudoku. It was 1rst grid of "killer IV" of krtek's cup. you need to login to see the grid, the archives are not updated.
But the rule was a bit different, as "number in one cage should be different" applied there.

Fred

Serkan has mentioned to me how much time he expects a top solver would take to complete all sudokus, so I obviously know the answer
But since he didn't answer the post yet, I'm not sure if he wants to make it public before the test ends.

As done in all other tests, your last submission (from online or paper mode) will be considered as the only valid answer.
We don't check intermediate submissions. So you get 50.

About "Number 5 Still Alive"

Serkan and Cihan did a contest just before WSC2007 - It had Number 5 Still Alive (and also Crossnumber, Distance) - Here is the link http://www.otuzoyun.com/puzzles/PseudokuChampionship.pdf


Any idea why it is called "Number 5 Still Alive". Is it based on some movie or song name?

Interestingly, a Google search on < "number 5 still alive" Sudoku > throws up a link which has the actual puzzle in the competition.

Some more examples at http://forsmarts.com/pdf/fpb_05.pdf
As noted in IB (like what Fred mentioned), in the puzzle in this competition "digits may repeat in the cages".

1] For online mode, will the rows/columns be automatically marked from the start, or will we need to click on "show cells to fill" 21 times?

2] For offline mode, how do we fill the answer key for "Just One Cell sudoku"? Just the number or the cell notation too? For online mode, I presume we just need to fill the key cell and click on submit.

I think the name could be fall out of puzzles like XV and kropki where 5 cannot be derived from cell where clues are given... just a wild thought

Edited by utkaarsh 2011-07-15 1:33 PM

Announcements

D1 - Musketry Sudoku will have 2 diagonals marked. These diagonals are 12-cells long. All other puzzles will have a combination of 2 rows / columns marked. See note below for E4 - Just One Cell Sudoku

Online Solvers
1) The order of Sudokus will be exactly same as in IB, except that D2 will appear before D1.
2) E4 - Just One Cell Sudoku - You must fill exactly one digit in the grid. If multiple digits are filled in the grid while submitting, you won't get any points. It is okay to have pencil marks around the grid (you don't need to clear the pencil marks before submitting)

Paper Solvers
1) The password protected puzzle booklet has 12 pages. There is no cover page. D1 and E5 appear on single pages. All other pages have 2 puzzles each
2) E4 - Just One Cell Sudoku - The answer format is "Co-ordinate of the cell, followed by the digit in the cell" e.g. EN3 (No special characters, you enter exactly 2 letters and one digit). See image below for co-ordinate system.
3) Paper solvers who don't want the grids to be loaded in their browser can use this link - http://logicmastersindia.com/M201107S/?paper=1


As usual, players are free to choose the mode of solving (paper or online or mixed). Your last submitted answer and its timestamp will be considered for scoring.
Point claims for typos will not be accepted, unless the typo is on a given digit.

It is almost certainly referring to the movie "Short circuit".

number 5 still alive is known to be very tricky. It is based on a principle that you can apply to "classic killer" sudoku. That is, you just have to add-up the unit digits, forgetting about the tens. The leftovers, together with the known areas, have to sum up ?5. For example, if your dotted areas show the digits: ?4, ?3, ?1 the sum is ?8. Any leftover cell or group of cells must end up with ?7, as ?8+?7 is ?5.

That is, because you want the sum to be 45, so it must end with a 5.

Like this, in the number 5 still alive, all of the areas have ?5, so the sum can either be ?5 or ?0, letting you figure out what the leftovers can be.

Puzzle booklet uploaded and flash submission enabled.

Score page is now enabled - http://logicmastersindia.com/M201107S/score.asp

Great contest!
Time limit was perfectly fixed. Also very good points distribution , maybe besides Just One Cell - it took me at most 5 seconds. ;)
The best puzzle constructions: Numeral, Double Diagonal, Termometer, Number 5, Killer.
Congratulations to You, Serkan.