Comments on: How to solve the Dodgson’s Doublets Puzzle in SQL

By: newkid

newkid — Fri, 25 Jun 2010 13:47:45 +0000

WITH w AS (
SELECT word
,UPPER(SUBSTR(word,rn,1)) c
,rn
FROM dictionary, (SELECT ROWNUM rn FROM DUAL CONNECT BY ROWNUM<=(SELECT MAX(LENGTH(word)) FROM dictionary))
WHERE rn<=LENGTH(word)
)
,l AS (SELECT w1.word w1,w2.word w2
FROM w w1,w w2
WHERE LENGTH(w1.word)=LENGTH(w2.word) AND w1.rn=w2.rn
AND w1.word<>w2.word
GROUP BY w1.word,w2.word
HAVING COUNT(CASE WHEN w1.c=w2.c THEN 1 END)=MAX(LENGTH(w1.word))-1
)
SELECT *
FROM (
SELECT SYS_CONNECT_BY_PATH(w1,’,')||’,'||:end_str
FROM l
WHERE UPPER(w2) = UPPER(:end_str)
START WITH UPPER(w1) = UPPER(:begin_str)
CONNECT BY NOCYCLE w1 = PRIOR w2 AND UPPER(PRIOR w2) != UPPER(:end_str)
ORDER BY LEVEL
)
WHERE ROWNUM=1;

SYS_CONNECT_BY_PATH(W1,’,')||’,'||:END_STR
————————————————-
,HEAD,heal,teal,tell,tall,tail

By: newkid

newkid — Thu, 24 Jun 2010 22:09:03 +0000

WITH w AS (
SELECT word
      ,UPPER(SUBSTR(word,rn,1)) c
      ,rn
  FROM dictionary, (SELECT ROWNUM rn FROM DUAL CONNECT BY ROWNUM<=(SELECT MAX(LENGTH(word)) FROM dictionary))
 WHERE rn<=LENGTH(word)
)
,l AS (SELECT w1.word w1,w2.word w2
  FROM w w1,w w2
 WHERE LENGTH(w1.word)=LENGTH(w2.word) AND w1.rn=w2.rn
       AND w1.word != w2.word
GROUP BY w1.word,w2.word
HAVING COUNT(CASE WHEN w1.c=w2.c THEN 1 END)=MAX(LENGTH(w1.word))-1
)
SELECT *
  FROM (
SELECT SYS_CONNECT_BY_PATH(w1,',')||','||:end_str
 FROM l
WHERE UPPER(w2) = UPPER(:end_str)
 START WITH UPPER(w1) = UPPER(:begin_str)
CONNECT BY NOCYCLE w1 = PRIOR w2 AND UPPER(PRIOR w2) != UPPER(:end_str)
ORDER BY LEVEL
)
WHERE ROWNUM=1;

By: newkid

newkid — Thu, 24 Jun 2010 22:07:33 +0000

WITH w AS (
SELECT word
      ,UPPER(SUBSTR(word,rn,1)) c 
      ,rn
  FROM dictionary, (SELECT ROWNUM rn FROM DUAL CONNECT BY ROWNUM<=(SELECT MAX(LENGTH(word)) FROM dictionary))
 WHERE rn<=LENGTH(word)
)
,l AS (SELECT w1.word w1,w2.word w2
  FROM w w1,w w2
 WHERE LENGTH(w1.word)=LENGTH(w2.word) AND w1.rn=w2.rn
       AND w1.word != w2.word
GROUP BY w1.word,w2.word
HAVING COUNT(CASE WHEN w1.c=w2.c THEN 1 END)=MAX(LENGTH(w1.word))-1
)
SELECT *
  FROM (
SELECT SYS_CONNECT_BY_PATH(w1,',')||','||:end_str
 FROM l
WHERE UPPER(w2) = UPPER(:end_str)
 START WITH UPPER(w1) = UPPER(:begin_str)
CONNECT BY NOCYCLE w1 = PRIOR w2 AND UPPER(PRIOR w2) != UPPER(:end_str)
ORDER BY LEVEL
)
WHERE ROWNUM=1;


SYS_CONNECT_BY_PATH(W1,',')||','||:END_STR
-------------------------------------------------
,HEAD,heal,teal,tell,tall,tail

By: newkid

newkid — Thu, 24 Jun 2010 20:41:57 +0000

oops…I missed that one!

By: Frank Zhou

Frank Zhou — Thu, 24 Jun 2010 19:22:14 +0000

Hi NewKid,

Please read all the rules carefully.

The letters must not be interchanged among themselves,
**** but each must keep to its own place ***

The translate can not guarantee the “position” of the letters.

Thanks for give this problem a try !

Frank

By: newkid

newkid — Thu, 24 Jun 2010 17:26:22 +0000

Forgot to check the length in connect by:

SELECT chain
  FROM (
SELECT SYS_CONNECT_BY_PATH(word,'->') chain,LEVEL lvl,word
  FROM dictionary 
 START WITH UPPER(word) = UPPER(:begin_str)
 CONNECT BY NOCYCLE wordPRIOR word AND LENGTH(TRANSLATE(UPPER(word),'$'||UPPER(PRIOR word),'$'))=1
         AND LENGTH(word) = LENGTH(PRIOR word)
)
WHERE UPPER(word) = UPPER(:end_str);

By: newkid

newkid — Thu, 24 Jun 2010 17:19:57 +0000

SELECT chain
  FROM (
SELECT SYS_CONNECT_BY_PATH(word,'->') chain,LEVEL lvl,word
  FROM dictionary 
 START WITH UPPER(word) = UPPER(:begin_str)
 CONNECT BY NOCYCLE wordPRIOR word AND LENGTH(TRANSLATE(UPPER(word),'$'||UPPER(PRIOR word),'$'))=1
)
WHERE UPPER(word) = UPPER(:end_str);

CHAIN
-------------------------------------------------------------
->HEAD->heal->tall->TAIL
->HEAD->heal->tall->teal->TAIL
->HEAD->heal->tall->tell->teal->TAIL
->HEAD->heal->tall->toll->tell->teal->TAIL
->HEAD->heal->teal->TAIL
->HEAD->heal->teal->toll->tall->TAIL
->HEAD->heal->teal->toll->tell->tall->TAIL
->HEAD->heal->tell->tall->TAIL
->HEAD->heal->tell->tall->teal->TAIL
->HEAD->heal->tell->teal->TAIL
->HEAD->heal->tell->teal->toll->tall->TAIL
->HEAD->heal->tell->toll->tall->TAIL
->HEAD->heal->tell->toll->tall->teal->TAIL