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=AWK/Primes/FSOE= |
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==AWK/Primes/FSOE1== |
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FSOE1 needs a number:set mapping and expressing this in AWK would blow up the code too much. (Or shorter: Maybe later.) |
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==AWK/Primes/FSOE3== |
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<lang awk>BEGIN { |
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n=2 |
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while( n<100 ) { |
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if( n in L ) { |
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p=L[n] |
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del L[n] |
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} else { |
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p=n |
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printf n " " |
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} |
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npp=n+p |
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while( npp in L ) |
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npp=npp+p |
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L[npp]=p |
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n++ |
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} |
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print |
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}</lang> |
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{{out}} |
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<pre> |
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2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 |
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</pre> |
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=BASH/Self Modyfying Code= |
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<pre> |
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$ . Thing-1033909978 |
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$ type Thing |
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Thing is a function |
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Thing () |
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{ |
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local get='shift;local __=$1;shift;echo ${!__}' set='shift;__=$1;shift;local $__="$*";eval "$FUNCNAME () { local $(local | tr "\n" " "); $(type $FUNCNAME | tail +5)"' version=1033909978; |
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eval ${!1} |
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} |
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$ Thing get version |
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1033909978 |
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$ date -d@$(Thing get version) # ;-) |
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Sun Oct 6 13:12:58 UTC 2002 |
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$ ## |
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$ ## add a new property 'show' |
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$ ## |
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$ Thing set show local |
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$ ## |
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$ ## try it |
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$ ## |
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$ Thing show |
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get='shift;local __=$1;shift;echo ${!__}' |
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set='shift;__=$1;shift;local $__="$*";eval "$FUNCNAME () { local $(local | tr "\n" " "); $(type $FUNCNAME | tail +5)"' |
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show=local |
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version=1033909978 |
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</pre> |
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=Dc/Questions/DROP= |
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TODO Drop top of stack without side effects |
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<pre> |
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# assume there is a value in x[1337], e.g. "gold" |
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[gold] 1337 :x |
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# "trash" on the stack: |
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[trash] |
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# push x[1337] to x-stack |
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1337;x Sx |
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# deposit TOS in x[1337] |
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1337: |
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# top of x-stack to x[1337] |
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Lx 1337: |
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1337 ;x |
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[Stack: ]PAP f |
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</pre> |
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{{out}} |
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<pre> |
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Stack: |
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gold |
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</pre> |
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Sigh! |
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Is there really no simpler way to drop the top of stack that works for strings and numbers and in all versions of Dc? |
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=Python/Primes/FSOE= |
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{{works with|Python|2.x}} |
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This is a sequentialised variant of the well known sieve method (ab)using a dictionary as sparse array. |
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Alternatively you can describe it as finding the wheels and moving them on a tape. The only knowledge is to start looking 2 instead of starting with 1, but the original sieve does skip 1 too. 2 is not hard coded to be prime. The algorithm detects it as 1st prime and then puts the 2-wheel on the tape. |
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==Python/Primes/FSOE1== |
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Variant: A tape position can hold multiple wheels. |
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<lang python>L = {} |
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n = 2 |
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while 1: |
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if n in L: |
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P = L[n] |
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del L[n] # optional - saves some memory. |
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else: |
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print n |
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P = [n] |
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for p in P: |
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npp = n+p |
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if npp in L: |
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L[npp].add(p) |
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else: |
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L[npp] = set([p]) |
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n += 1</lang> |
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{{out}} |
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<pre> |
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2 |
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3 |
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5 |
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7 |
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11 |
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13 |
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17 |
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19 |
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23 |
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29 |
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</pre> |
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...the program has to be terminated by the user e.g. by typing ctrl-c. |
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==Python/Primes/FSOE3== |
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{{works with|Python|2.x}} |
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Variant: A tape position can hold one wheel. |
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<lang python>L = {} |
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n = 2 |
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while 1: |
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if n in L: |
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P = L[n] |
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del L[n] # optional - saves some memory. |
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else: |
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P = n |
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print n |
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m = n+P |
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while m in L: |
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m += P |
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L[m] = P |
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n += 1</lang> |
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{{out}} |
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<pre> |
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2 |
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3 |
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5 |
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7 |
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11 |
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13 |
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17 |
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19 |
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23 |
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29 |
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</pre> |
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...the program has to be terminated by the user e.g. by typing ctrl-c. |
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---- |
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{{mylangbegin}} |
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{{mylang|AWK|}} |
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{{mylang|B|}} |
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{{mylang|BASH|}} |
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{{mylang|C|}} |
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{{mylang|Dc|}} |
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{{mylang|Spin|}} |
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{{mylangend}} |
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