Partition an integer x into n primes: Difference between revisions
add CLU
Not a robot (talk | contribs) (Add APL) |
Not a robot (talk | contribs) (add CLU) |
||
Line 532:
Partitioned 40355 with 3 primes 3+139+40213</pre>
=={{header|CLU}}==
<syntaxhighlight lang="clu">isqrt = proc (s: int) returns (int)
x0: int := s/2
if x0 = 0 then return(s) end
x1: int := (x0 + s/x0) / 2
while x1 < x0 do
x0, x1 := x1, (x0 + s/x0) / 2
end
return(x0)
end isqrt
primes = proc (n: int) returns (sequence[int])
prime: array[bool] := array[bool]$fill(1, n, true)
prime[1] := false
for p: int in int$from_to(2, isqrt(n)) do
for c: int in int$from_to_by(p*p, n, p) do
prime[c] := false
end
end
pr: array[int] := array[int]$predict(1, n)
for p: int in array[bool]$indexes(prime) do
if prime[p] then array[int]$addh(pr, p) end
end
return(sequence[int]$a2s(pr))
end primes
partition_sum = proc (x, n: int, nums: sequence[int])
returns (sequence[int])
signals (impossible)
if n<=0 cor sequence[int]$empty(nums) then signal impossible end
if n=1 then
for k: int in sequence[int]$elements(nums) do
if x=k then return(sequence[int]$[x]) end
end
signal impossible
end
k: int := sequence[int]$bottom(nums)
rest: sequence[int] := sequence[int]$reml(nums)
return(sequence[int]$addl(partition_sum(x-k, n-1, rest), k))
except when impossible:
return(partition_sum(x, n, rest))
resignal impossible
end
end partition_sum
prime_partition = proc (x, n: int)
returns (sequence[int])
signals (impossible)
return(partition_sum(x, n, primes(x))) resignal impossible
end prime_partition
format_sum = proc (nums: sequence[int]) returns (string)
result: string := ""
for n: int in sequence[int]$elements(nums) do
result := result || "+" || int$unparse(n)
end
return(string$rest(result, 2))
end format_sum
start_up = proc ()
test = struct[x: int, n: int]
tests: sequence[test] := sequence[test]$[
test${x:99809,n:1}, test${x:18,n:2}, test${x:19,n:3}, test${x:20,n:4},
test${x:2017,n:24}, test${x:22699,n:1}, test${x:22699,n:2},
test${x:22699,n:3}, test${x:22699,n:4}, test${x:40355,n:3}
]
po: stream := stream$primary_output()
for t: test in sequence[test]$elements(tests) do
stream$puts(po, "Partitioned " || int$unparse(t.x) || " with "
|| int$unparse(t.n) || " primes: ")
stream$putl(po, format_sum(prime_partition(t.x, t.n)))
except when impossible:
stream$putl(po, "not possible.")
end
end
end start_up</syntaxhighlight>
{{out}}
<pre>Partitioned 99809 with 1 primes: 99809
Partitioned 18 with 2 primes: 5+13
Partitioned 19 with 3 primes: 3+5+11
Partitioned 20 with 4 primes: not possible.
Partitioned 2017 with 24 primes: 2+3+5+7+11+13+17+19+23+29+31+37+41+43+47+53+59+61+67+71+73+79+97+1129
Partitioned 22699 with 1 primes: 22699
Partitioned 22699 with 2 primes: 2+22697
Partitioned 22699 with 3 primes: 3+5+22691
Partitioned 22699 with 4 primes: 2+3+43+22651
Partitioned 40355 with 3 primes: 3+139+40213</pre>
=={{header|D}}==
{{trans|Kotlin}}
| |||