Rosetta Code

Truncatable primes: Difference between revisions

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m →‎{{header|REXX}}: combined two statements into one line. -- ~~~~
m →‎{{header|REXX}}: made the L and R DO loops simplier. -- ~~~~
Line 1,405:
lp=0; rp=0
 
do jL=n by -1 until lp\==0; & rp\==0; if pos(0,p.jL)\==0 then iterate
do L do k=1 for length(p.L)-1; while lp_==0right(p.L,k) /*truncate a #.*/
if do\!._ k=1 forthen length(p.j)-1;iterate L _=right(p.j,k) /*truncate aTruncated # ¬ prime? Skip it. */
if \!._ then leave L end /*Truncated # ¬ prime? Skip it. k*/
lp=p.jL▼
end end /*kL*/
▲ lp=p.j
end /*L*/
 
do R=1n forby -1 while until rp\==0; if pos(0,p.R)\==0 then iterate
do k=1 for length(p.jR)-1; _=left(p.jR,k) /*truncate a #.*/
if \!._ then leaveiterate R /*Truncated # ¬ prime? Skip it. */
end /*k*/
rp=p.jR
end /*R*/
end /*j*/
 
say 'The largest left-truncatable prime under one million is ' lp
Retrieved from "https://rosettacode.org/wiki/Truncatable_primes"