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List rooted trees: Difference between revisions

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List rooted trees (view source)

Revision as of 03:45, 17 December 2020

1 byte removed ,  3 years ago
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start= 2**nn + (2**nn) % 2 /*calculate the starting decimal number*/
if N==1 then start= 2**1 /*treat the start for unity as special.*/
_@= copies('─', 20)"► "; o = 'o' /*demonstrative literal for solutions. */
#= 0 /*count of ways to nest bags (so far). */
$= /*string holds possible duplicious strs*/
do j=start + start//2 to 2**(nn+1)-1 by 2 /*limit the search, smart start and end*/
t= x2b( d2x(j) ) + 0 /*convert dec number to a binary string*/
z= length( space( translate(t, , 0), 0) ) /*count the number of zeros in bit str.*/
if z\==n then iterate /*Not enough zeroes? Then skip this T.*/
if N>1 then if left(t, N)==right(t, N) then iterate /*left side ≡ right side?*/
if N>2 then if right(t, 2)== 10 then iterate /*has a right─most isolated bag ?*/
if N>3 then if right(t, 4)== 1100 then iterate /* " " " " " */
if N>4 then if right(t, 6)==111000 then iterate /* " " " " " */
if N>4 then if right(t, 6)==110100 then iterate /* " " " " " */
if N>4 then if right(t, 6)==100100 then iterate /* " " " " " */
if wordpos(t, $)\==0 then iterate then iterate /*this a /*duplicate bag stuffing? */
say _ @ changestr('()', translate(t, "()", 10), 'O'o) /*show a compact display with oh.*/
#= # + 1 /*bump count of ways of nesting bags. */
$= $ translate( reverse(t), 01, 10) /*save a (possible) duplicious string. */
end /*j*/
say /*separate number─of─ways with a blank.*/
say # ' is the number of ways to nest' n "bags." /*stick a fork in it, we're all done. */</lang>
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