Edited at

多段階選抜 (Lua)

多段階選抜
解答日
シリーズ:yieldの練習/ジェネレータを入れ子に/整数平方根・立方根の実装

問題
 

http://nabetani.sakura.ne.jp/hena/ord24eliseq/
https://qiita.com/Nabetani/items/1c83005a854d2c6cbb69

Ruby
2014/8/2(当日)
https://qiita.com/cielavenir/items/9f15e29b73ecf98968a5

C#/Python
2014/8/4
https://qiita.com/cielavenir/items/a1156e6a4f71ddbe5dcb

 
ここから上はdrop_prev_square/drop_prev_cubicをまとめる前の答案

Go/C#/Ruby/Python
2014/8/5
https://qiita.com/cielavenir/items/2a685d3080862f2c2c47

PHP/JavaScript
2014/9/9
https://qiita.com/cielavenir/items/28d613ac3823afbf8407

VB
2014/9/10
https://qiita.com/cielavenir/items/cb7266abd30eadd71c04

D
2015/12/21
https://qiita.com/cielavenir/items/47c9e50ee60bef2847ec

Perl
2017/3/10
https://qiita.com/cielavenir/items/6dfbff749d833c0fd423

Lua
2017/3/13
https://qiita.com/cielavenir/items/c60fe7e8da73487ba062

C++20(TS)
2017/3/15

https://qiita.com/cielavenir/items/e1129ca185008f49cbab (MSVC)
https://qiita.com/cielavenir/items/1cfa90d73d11bb7dc3d4 (clang)

F#
2017/3/17
https://qiita.com/cielavenir/items/a698d6a26824ff53de81

Boo/Nemerle
2017/5/13
https://qiita.com/cielavenir/items/e2a783f0fe4b0fe0ed48

Perl6
2017/5/15
https://qiita.com/cielavenir/items/656ea17fa96c865c4498

Kotlin
2017/5/25
https://qiita.com/cielavenir/items/9c46ce8d9d12e51de285

Crystal
2018/5/8
https://qiita.com/cielavenir/items/1815bfa6a860fd1f90db

MoonScript
2018/6/16
https://qiita.com/cielavenir/items/8b03cce0386f4537b5ad

Julia/Rust
2018/12/20
https://qiita.com/cielavenir/items/3ddf72b06d625da0c4a5

Nim
2018/12/26
https://qiita.com/cielavenir/items/5728944867e609fd52a7

Tcl
2018/12/31
https://qiita.com/cielavenir/items/76cbd9c2022b48c9a2c9

Pascal/Cobra
2019/1/16
https://qiita.com/cielavenir/items/81b81baf8dfc1f877903

Icon
2019/1/17
https://qiita.com/cielavenir/items/889622dcc721f5a4da24

(icbrtの実装に関する)補題
2017/5/11
整数除算であってもn/(x*y)はn/x/yに等しい(ことの証明)
https://qiita.com/cielavenir/items/21a6711afd6be8c18c55

cbrtはlmathxパッケージを使用しています。不要になりました。


tyama_hena24_enum.lua

#!/usr/bin/env lua

-- http://qiita.com/Nabetani/items/1c83005a854d2c6cbb69
-- http://nabetani.sakura.ne.jp/hena/ord24eliseq/

-- require 'mathx' -- luarocks install lmathx

function isqrt(n)
if n<=0 then
return 0
end
if n<4 then
return 1
end
local x=0
local y=n
while x~=y and x+1~=y do
x=y
y=(n//y+y)//2
end
return x
end
function icbrt(n)
if n<0 then
return icbrt(-n)
end
if n==0 then
return 0
end
if n<8 then
return 1
end
local x=0
local y=n
while x~=y and x+1~=y do
x=y
y=(n//y//y+y*2)//3
end
return x
end

function generate()
return coroutine.create(function()
local i=1
while true do
coroutine.yield(i)
i=i+1
end
end)
end
function drop_prev(check,prev)
return coroutine.create(function()
local a,b
_,a=coroutine.resume(prev)
_,b=coroutine.resume(prev)
while true do
if not check(b) then
coroutine.yield(a)
end
a=b
_,b=coroutine.resume(prev)
end
end)
end
function drop_next(check,prev)
return coroutine.create(function()
local a,b
_,a=coroutine.resume(prev)
_,b=coroutine.resume(prev)
coroutine.yield(a)
while true do
if not check(a) then
coroutine.yield(b)
end
a=b
_,b=coroutine.resume(prev)
end
end)
end
function drop_n(check,n,prev)
return coroutine.create(function()
local i=0,a
while true do
i=i+1
_,a=coroutine.resume(prev)
if not check(i,n) then
coroutine.yield(a)
end
end
end)
end

function is_sq(n)
-- local x=math.floor(math.sqrt(n))
local x=isqrt(n)
return x*x==n
end
function is_cb(n)
local x=math.floor(math.cbrt(n))
return x*x*x==n
end
function is_multiple(i,n)
return i%n==0
end
function is_le(i,n)
return i<=n
end

local f={
['S']=function(e) return drop_next(is_sq,e) end,
['s']=function(e) return drop_prev(is_sq,e) end,
['C']=function(e) return drop_next(is_cb,e) end,
['c']=function(e) return drop_prev(is_cb,e) end,
['h']=function(e) return drop_n(is_le,100,e) end,
}
local i,r
for i=2,9 do
f[tostring(i)]=function(e) return drop_n(is_multiple,i,e) end
end
local line=io.read('*line')
while line~=nil do
local g=generate()
for c in line:gmatch('.') do
g=f[c](g)
end
for i=1,10 do
if i>1 then
io.write(',')
end
_,r=coroutine.resume(g)
io.write(r)
end
io.write("\n")
io.flush()
line=io.read('*line')
end