Re: Checking for All-Different Characters

Here is a simple brute force approach with the same count

m.cnt = 0 m.Cdate = {^1900-01-01} DO WHILE m.Cdate < {^9999-12-31} m.str = dtos(m.cdate) FOR m.x = 1 TO 8 IF OCCURS(SUBSTR(m.str, m.x, 1), m.str) > 1 EXIT ENDIF ENDFOR IF m.x = 9 m.cnt = m.cnt + 1 * WAIT window m.Cdate ENDIF m.cdate = m.cdate + 1 ENDDO ?m.cnt

It takes a little over 6 seconds on my machine so it's not faster - just simpler.

Joe

On Sun, Jul 17, 2016 at 9:06 PM, Darren foxdev@ozemail.com.au wrote:

This will give you all the dates that have a unique set of digits 1900 to 9999 - probably more efficient ways to do it but this runs sub second on my machine and spits out 44,640 values. Have not done any testing or checking but it'll give you at least an idea.

CREATE CURSOR w_dates (uniquedate D)

FOR lnYear = 1900 TO 9999

STORE 0 TO lnCheck STORE .F. TO llDuplicate

*- Check the year part for duplicate number usage STORE STR(m.lnYear, 4) TO lcYear FOR n = 1 TO 4

STORE VAL(SUBSTR(m.lcYear, n, 1)) TO lnVal

IF BITTEST(m.lnCheck, m.lnVal)
  STORE .T. TO llDuplicate
  EXIT
ELSE
  lnCheck = BITSET(m.lnCheck, m.lnVal)
ENDIF

ENDFOR

IF m.llDuplicate LOOP ENDIF

STORE m.lnCheck TO lnCheckYr

*------------------------------------------- *- Process Months *------------------------------------------- FOR lnMth = 1 TO 12

*- Check the mth + year part for duplicate number usage
STORE .F. TO llDuplicate

STORE PADL(m.lnMth, 2, "0") TO lcMth
FOR n = 1 TO 2

STORE VAL(SUBSTR(m.lcMth, n, 1)) TO lnVal

  IF BITTEST(m.lnCheck, m.lnVal)
    STORE .T. TO llDuplicate
    EXIT
  ELSE
    lnCheck = BITSET(m.lnCheck, m.lnVal)
  ENDIF

ENDFOR

IF m.llDuplicate

  STORE m.lnCheckYr TO lnCheck  && Restore baseline to the year value
  LOOP

ENDIF

STORE m.lnCheck TO lnCheckYrMth

*-------------------------------------------
*- Process Days
*-------------------------------------------

*- How many days in the month ?
lnDays = ICASE(;
  INLIST(m.lnMth, 1, 3, 5, 7, 8, 10, 12), 31, ;
  m.lnMth = 2, 28, ;
  30)

*- Is this a leap Year ?
IF m.lnMth = 2 AND MOD(m.lnYear, 4) = 0 AND IIF(MOD(m.lnYear, 100) = 0,

IIF(MOD(m.lnYear, 400) = 0, .T., .F.), .T.) STORE 29 TO lnDays ENDIF

FOR lnDay = 1 to m.lnDays

  *- Check the mth + year + day parts for duplicate number usage
  STORE .F. TO llDuplicate

  STORE PADL(m.lnDay, 2, "0") TO lcDay
  FOR n = 1 TO 2

  STORE VAL(SUBSTR(m.lcDay, n, 1)) TO lnVal

    IF BITTEST(m.lnCheck, m.lnVal)
      STORE .T. TO llDuplicate
      EXIT
    ELSE
      lnCheck = BITSET(m.lnCheck, m.lnVal)
    ENDIF

  ENDFOR

  IF NOT m.llDuplicate

    INSERT INTO w_dates (;
        uniquedate) ;
      VALUES (;
        DATE(m.lnYear, m.lnMth, m.lnDay))

  ENDIF

  STORE m.lnCheckYrMth TO lnCheck  && Restore baseline to the year +

month value - check next day in month.

ENDFOR

STORE m.lnCheckYr TO lnCheck  && Check Next Mth in Year

ENDFOR

ENDFOR

-----Original Message----- From: ProfoxTech [mailto:profoxtech-bounces@leafe.com] On Behalf Of Gene Wirchenko Sent: Monday, 18 July 2016 2:29 AM To: profoxtech@leafe.com Subject: Checking for All-Different Characters

Hello:

  I write a logic/math puzzle each week.  They appear in my blog

(http://genew.ca/) and two local newspapers.

  Here is the latest problem:

  "Consider a date in YYYY-MM-DD format.  What is the next date where

all eight digits will be different?"

  I solved this by hand.  I decided to verify my solution with a

program. I often cook up something in GW-BASIC, but since VFP has date functions, I decided to go with it.

  It was very easy to set up the framework of the loop.  What threw me

for a loop is how to check that all of the digits are different. I ended up converting the date to string with dtos() and then testing the string with a rather ugly-looking condition. Is there something faster?

***** Start of Code *****

• 16s-16.prg

• Date Puzzle

• Last Modification: 2016-07-17

• Consider a date in YYYY-MM-DD format. What is the next date where all

• eight digits will be different?

  ? "*** Execution begins." ? program() close all clear all

  set talk off set exact on set century on set date ansi

  local startdate startdate=date()

  ? "Start Date: "+transform(startdate)

  local trydate, looping trydate=startdate looping=.t. do while looping

   local trydtos
   trydtos=dtos(trydate)
   if right(trydtos,4)="0101"
      ? "Working on year "+left(trydtos,4)
      endif
  
   if;
    iif("0"$trydtos,1,0)+;
    iif("1"$trydtos,1,0)+;
    iif("2"$trydtos,1,0)+;
    iif("3"$trydtos,1,0)+;
    iif("4"$trydtos,1,0)+;
    iif("5"$trydtos,1,0)+;
    iif("6"$trydtos,1,0)+;
    iif("7"$trydtos,1,0)+;
    iif("8"$trydtos,1,0)+;
    iif("9"$trydtos,1,0)#8
      trydate=trydate+1
   else     && solution
      looping=.f.
      endif
  
   enddo
  
  

  ? "Solution is "+transform(trydate)+"."

  close all clear all ? "*** Execution ends." return

***** End of Code *****

Sincerely,

Gene Wirchenko

[excessive quoting removed by server]