40 lines
1.3 KiB
Text
40 lines
1.3 KiB
Text
# An example
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.maxwidth 100
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set variable game='85 24 72 9 4 1 7 23 5 9 4 8 7 17 36 4 ';
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create or replace function instr3(s,t,j) as (
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select case when n = 0 then 0
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else n + j - 1
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end
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from (select instr(substr(s,j), t) as n)
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);
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with recursive
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symbols (d) as (select level::VARCHAR from range(1,10) t(level) )
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, board (i) as (select level from range(1,82) t(level) )
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, neighbors (i, j) as (
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select b1.i, b2.i
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from board b1 inner join board b2
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on b1.i != b2.i
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and (
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mod(b1.i - b2.i, 9) = 0
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or ceil(b1.i / 9) = ceil(b2.i / 9)
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or ceil(b1.i / 27) = ceil(b2.i / 27) and trunc(mod(b1.i - 1, 9) / 3) = trunc(mod(b2.i - 1, 9) / 3)
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)
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)
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, r (str, pos) as (
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select getvariable('game'), instr(getvariable('game'), ' ')
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union all
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select substr(r.str, 1, r.pos - 1) || s.d || substr(r.str, r.pos + 1), instr3(r.str, ' ', r.pos + 1)
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from r inner join symbols s
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on r.pos > 0 and not exists (
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select *
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from neighbors n
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where r.pos = n.i and s.d = substr(r.str, n.j, 1)
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)
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)
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select str
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from r
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where pos = 0
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;
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