Prime triangle: Difference between revisions
→{{header|Julia}}
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=={{header|Julia}}==
=== Filter method ===
<lang julia>using Combinatorics
function primetriangle(nrows::Integer)
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[1, 1, 1, 1, 1, 2, 4, 7, 24, 80, 216, 648, 1304, 3392, 13808, 59448]
36.933227 seconds (699.10 M allocations: 55.557 GiB, 46.71% gc time, 0.37% compilation time)
</pre>
=== Generator method ===
Similar to the Phix entry.
<lang julia>using Primes
function solverow(row, pos, avail)
results, nresults = Int[], 0
for (i, tf) in enumerate(avail)
if tf && isprime(row[pos - 1] + i + 1)
if pos >= length(row) - 1 && isprime(row[end] + i + 1)
row[pos] = i + 1
return (copy(row), 1)
else
row[pos] = i + 1
newav = copy(avail)
newav[i] = false
newresults, n = solverow(copy(row), pos + 1, newav)
nresults += n
results = isempty(results) && !isempty(newresults) ? newresults : results
end
end
end
return results, nresults
end
function primetriangle(nrows::Integer)
nrows < 2 && error("number of rows requested must be > 1")
counts, rowstrings = [1; zeros(Int, nrows - 1)], ["" for _ in 1:nrows]
for r in 2:nrows
p, n = solverow(collect(1:r+1), 2, trues(r - 1))
rowstrings[r] = prod([lpad(n, 3) for n in p]) * "\n"
counts[r] = n
end
println(" 1 2\n" * prod(rowstrings), "\n", counts)
end
</lang> {{out}}
<pre>
1 2
1 2 3
1 2 3 4
1 4 3 2 5
1 4 3 2 5 6
1 4 3 2 5 6 7
1 2 3 4 7 6 5 8
1 2 3 4 7 6 5 8 9
1 2 3 4 7 6 5 8 9 10
1 2 3 4 7 10 9 8 5 6 11
1 2 3 4 7 10 9 8 5 6 11 12
1 2 3 4 7 6 5 12 11 8 9 10 13
1 2 3 4 7 6 13 10 9 8 11 12 5 14
1 2 3 4 7 6 13 10 9 8 11 12 5 14 15
1 2 3 4 7 6 5 12 11 8 15 14 9 10 13 16
1 2 3 4 7 6 5 12 11 8 9 10 13 16 15 14 17
1 2 3 4 7 6 5 8 9 10 13 16 15 14 17 12 11 18
1 2 3 4 7 6 5 8 9 10 13 16 15 14 17 12 11 18 19
1 2 3 4 7 6 5 8 9 10 13 16 15 14 17 12 19 18 11 20
[1, 1, 1, 1, 1, 2, 4, 7, 24, 80, 216, 648, 1304, 3392, 13808, 59448, 155464, 480728, 1588162]
25.818809 seconds (249.58 M allocations: 22.295 GiB, 15.56% gc time)
</pre>
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