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]