FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in          Games  Calendar Log in to check your private messages    Solving wapati's grids by guessing Goto page Previous  1, 2, 3  Next          Sudoku Programmers Forum Index -> Puzzles View previous topic :: View next topic   Author Message Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Wed Feb 06, 2008 9:06 am    Post subject: An easy grid is shown below, despite it is commonly evaluated as diabolic. Such estimations are generally done by computer programs not by human mind! Due to the simple solution by direct guessing, no scheme is presented in HTM link. Code: # # wapati's grid of Feb.04,2008 # 8 . 3|. . 4|. . . . 5 6|. . 7|9 . . 1 4 .|. . .|. 8 3 -----+-----+----- . . .|. 2 .|. 7 . . . .|6 . .|. . . 4 3 .|. . .|6 . 2 -----+-----+----- . 6 .|. . 5|. 9 . . . 8|7 . .|3 . . . . 1|. . 6|. . 5 # # Rows: A..I, Cols: 1..9 # #   9E1 (alias 9E1) [contradiction] #   9E1 -> solves directly the puzzle, #          with the help of: #       row D  18   18  #       row E  18    4  (Pair 18 in E9) #             Col2 Col7 # Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Wed Feb 06, 2008 4:49 pm    Post subject: One tree plus one bifurcation easily solve next grid. See here its scheme: http://img37.picoodle.com/img/img37/4/2/6/f_wap05febm_8b26f56.jpg Code: # # wapati's grid of Feb.05,2008 # . 7 .|. 5 .|8 1 . 4 . .|. 8 .|. . . . . .|7 . 2|. . . -----+-----+----- . . 2|9 7 .|. 6 . 6 5 .|1 . 8|. 7 . . . 9|. 4 .|. . . -----+-----+----- 8 . .|. . .|. . . 3 . .|2 1 .|. . 7 . . .|. . .|. 2 4 # #   ----- 1st Tree ----- #   1) 9B8 (alias 9G8) #       | #       +-- 5F4 (alias 5G4) [mark ^] #           which immediately solves the puzzle # # *****  PAUSE for a couple of months   ***** #       (only some glances for replies) # ******************************************* # Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Sat Feb 09, 2008 10:48 am    Post subject: Hi wapati, could you please let me know if the following grid is solvable with one (or more) of your sudoku techniques? I found it tough enough for hand-solvers (like me). Thanks Frank In next link are shown two solution phases: intermediate and final: http://img26.picoodle.com/img/img26/4/2/9/f_1612215m_e75bc0b.jpg Note: the jpeg imagine should be magnified after download, to be clear. Code: # # Source: Puzzle Designer of `The Su Doku Assistant`(v1.9) #         seed 1612, 21 starting cells, 5 grade of difficulty #         symmetric grid #         (max.grade of diff.=6, often not for human minds!) # . . 4|5 . 1|. . . . . .|. 3 .|. . 8 . 9 .|. . .|6 . . -----+-----+----- . . 6|. . .|1 . . 3 . .|. 5 .|. . 4 . . 2|. . .|9 . . -----+-----+----- . 5 .|. . .|. 2 . 7 . .|. 4 .|. . . . . .|7 . 9|6 . . # #      ----- 1st Tree ----- #    (Trial with Pair cells, on/off cells unavailable!) #  1) Pair 78, block 6, row E (alias 2E7) #     see intermediate step -> failure #     so, 2E7 is definitive (circled) # #      ----- 1st Tree ----- #       (see final phase) #  1) 6G5 (alias 6A5) #      | #      +-- 1I5 (alias 1F5) (mark ^) #           | #           +-- 4G7 (alias 4B7) (mark o) #               which solves the `strong` puzzle # Back to top daj95376 Joined: 05 Feb 2006 Posts: 349 : Items Posted: Sat Feb 09, 2008 5:56 pm    Post subject: Frank, I suggest that you check your puzzle above with the original puzzle. The one above has 249 solutions and isn't a valid Sudoku puzzle. Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Sat Feb 09, 2008 9:08 pm    Post subject: daj95376 wrote: Frank, I suggest that you check your puzzle above with the original puzzle. The one above has 249 solutions and isn't a valid Sudoku puzzle. You are a quick reader, daj95376!! Also, my school boy is so cleaver to understand that 6 in C7 should be placed in C8. Typesetting mismatch, I mean. The exact scheme was shown in the link mentioned in my post; I repeat it for your memo. Here: http://img26.picoodle.com/img/img26/4/2/9/f_1612215m_e75bc0b.jpg So, next time, daj95376, be careful before posting anything. Nevertheless, thanks for your post and try to solve the grid. Back to top rkral Joined: 21 Oct 2005 Posts: 233 : Items Posted: Sat Feb 09, 2008 11:09 pm    Post subject: Frank wrote: So, next time, daj95376, be careful before posting anything. Nevertheless, thanks for your post and try to solve the grid. Frank, that sounds like you're admonishing daj95376 for believing your typo(s). I hope that's not what you meant. Back to top wapati Joined: 12 Jun 2007 Posts: 622 : Location: Canada Items Posted: Sun Feb 10, 2008 5:39 am    Post subject: Frank wrote: Hi wapati, could you please let me know if the following grid is solvable with one (or more) of your sudoku techniques? I found it tough enough for hand-solvers (like me). Thanks Frank The grid you posted could be easy, because there are many answers. The corrected grid (not posted) isn't one I could solve on paper, my method of choice. (To me that is hand solving, pencil and paper.) ANY correct puzzle can be solved by guessing. I don't see what your position is. Back to top wapati Joined: 12 Jun 2007 Posts: 622 : Location: Canada Items Posted: Sun Feb 10, 2008 5:44 am    Post subject: Frank wrote: daj95376 wrote: Frank, I suggest that you check your puzzle above with the original puzzle. The one above has 249 solutions and isn't a valid Sudoku puzzle. You are a quick reader, daj95376!! Also, my school boy is so cleaver to understand that 6 in C7 should be placed in C8. Typesetting mismatch, I mean. The exact scheme was shown in the link mentioned in my post; I repeat it for your memo. Here: http://img26.picoodle.com/img/img26/4/2/9/f_1612215m_e75bc0b.jpg So, next time, daj95376, be careful before posting anything. Nevertheless, thanks for your post and try to solve the grid. daj is a friend and a well respected member of this community. His post was fair and accurate. I am offended by your reply. Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Sun Feb 10, 2008 8:02 am    Post subject: To wapati I'm fully disagree with you. The daj's post should be written in this polite form: "It seems that your grid presents 249 solutions, please check it". But, pedantically, he didn't check my jpeg available in the same post, where the corrected scheme was stored. Directly (I imagine,so) he copy-and-pasted that grid, filled in a computer program and, satisfied, procounced his superb sentence: "You are wrong!". The same error of him (daj) you (wapati) has done in the answer above. So, finally, the proper grid is: Code: # . . 4|5 . 1|. . . . . .|. 3 .|. . 8 . 9 .|. . .| .6 . -----+-----+----- . . 6|. . .|1 . . 3 . .|. 5 .|. . 4 . . 2|. . .|9 . . -----+-----+----- . 5 .|. . .|. 2 . 7 . .|. 4 .|. . . . . .|7 . 9|6 . . # #       For readers who want to contact me, here is my anti-spam mail address: # #               1@2.3, being 3= com; 2= aol; 1= viatorino37 # #      ===================================================================== # Back to top gsf Joined: 18 Aug 2005 Posts: 411 : Location: NJ USA Items Posted: Mon Feb 11, 2008 5:38 am    Post subject: Frank wrote: To wapati I'm fully disagree with you. The daj's post should be written in this polite form: "It seems that your grid presents 249 solutions, please check it". But, pedantically, he didn't check my jpeg available in the same post, where the corrected scheme was stored. Directly (I imagine,so) he copy-and-pasted that grid, filled in a computer program and, satisfied, procounced his superb sentence: "You are wrong!". any post containing an invalid grid, gone uncorrected, is a disservice to current and future forum perusers the post should be corrected by editing to avoid future problems by future searches that may pull in the post without reading the thread context I also feel that any grid not in text [ code ] ... [ /code ] form is secondary why? mouse snarf failure rate <<< type in by hand failure rate if there is a discrepancy between a properly formatted grid and a pixelated grid then it is incumbent on the poster to fix it for manners, try posting an invalid grid on some other (unnamed) sudoku forums and see what happens also, my solver complains before even attempting to solve Code: sudoku: frank.bad:11: invalid cell [97]=6 daj, how did you get 249 solutions with multiple 6's in the same column? Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Mon Feb 11, 2008 7:46 am    Post subject: To gsf. You are right! My ill typesetted grid, issued last saturday, has a clear conflict on 6's repeated two times in column 7. Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Mon Feb 11, 2008 12:02 pm    Post subject: Please, does somebody know how I may perform the forum operations red square marked in next image? http://img34.picoodle.com/img/img34/4/2/11/f_editm_557f36f.jpg Thanks a lot, Frank Back to top rkral Joined: 21 Oct 2005 Posts: 233 : Items Posted: Mon Feb 11, 2008 1:56 pm    Post subject: gsf wrote: daj, how did you get 249 solutions with multiple 6's in the same column? angusj's Simple Sudoku discards the conflicting digit 6 in row 9 without giving an error message -- other than the "249 solutions." Frank wrote: does somebody know how I may perform the forum operations red square marked in next image? There is an "edit" button in the upper right corner of your post. When your post is the last post on a thread, there is also and "X' button for deleting. Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Mon Feb 11, 2008 5:57 pm    Post subject: Quote: There is an "edit" button in the upper right corner of your post. When your post is the last post on a thread, there is also and "X' button for deleting. Nice info, rkral! I want to better page my first posts, truly unreadable up to now. Thank you very much. Back to top Frank Joined: 24 Jan 2008 Posts: 29 : Location: Italy Items Posted: Tue Feb 12, 2008 10:09 am    Post subject: To rkral or somebody else. My question in 3 items: 1.. My browser FireFox 2.0.0.12 has a strange behaviour when it is activated under Linux/Ubuntu 7.10: columns are not vertically aligned, as shown below, while no problems arise under Windows-Xp. http://img30.picoodle.com/img/img30/4/2/12/f_gridm_824bf47.png 2.. I'd like to edit my thread title, by a slight add "Solving wapati's (+alias) grids by guessing". Which commands do I need to do so? 3.. Impossible to clear definitively a post. No "X" found, as suggested by rkral a couple of posts above. The only way is to leave there some dots ...., as I've done. 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