30 lines
1.0 KiB
MySQL
30 lines
1.0 KiB
MySQL
with
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symbols (d) as (select to_char(level) from dual connect by level <= 9)
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, board (i) as (select level from dual connect by level <= 81)
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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 :game, instr(:game, ' ')
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from dual
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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), instr(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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