Comments on: How to solve the Stamp Combo Puzzle in SQL

By: newkid

newkid — Mon, 28 Jun 2010 19:53:48 +0000

WITH c  AS (SELECT 3 cnt FROM DUAL UNION ALL SELECT 4 FROM DUAL)
,stamps AS (SELECT c1.cnt||c2.cnt||c3.cnt||c5.cnt||c10.cnt AS all_cnt
                  ,c1.cnt+2*c2.cnt+3*c3.cnt+5*c5.cnt+10*c10.cnt AS val
                  ,'1*'||c1.cnt||'+2*'||c2.cnt||'+3*'||c3.cnt||'+5*'||c5.cnt||'+10*'||c10.cnt AS result
              FROM c c1,c c2,c c3,c c5,c c10
            )
SELECT result||'='||val from stamps
WHERE MOD(val,10)=0
      AND LENGTH(all_cnt)-LENGTH(REPLACE(all_cnt,'4'))=2
      AND LENGTH(all_cnt)-LENGTH(REPLACE(all_cnt,'3'))=3
      ;

RESULT||'='||VAL
-------------------------------------
1*3+2*4+3*3+5*4+10*3=70

By: newkid

newkid — Mon, 28 Jun 2010 13:57:55 +0000

Recursive WITH in 11GR2:

WITH t(lvl,val,left_4,left_3,result) AS (
  SELECT 0,0,2,3,'' FROM DUAL
  UNION ALL
  SELECT t.lvl+1
        ,t.val+s.price*cnt
        ,left_4 - DECODE(cnt,4,1,0)
        ,left_3 - DECODE(cnt,3,1,0)
        ,t.result||' '||s.price||'*'||cnt
    FROM t
        ,(SELECT ROWNUM price_id,DECODE(ROWNUM,4,5,5,10,ROWNUM) AS price FROM DUAL CONNECT BY ROWNUM<=5) s
        ,(SELECT 4 as cnt FROM DUAL UNION ALL SELECT 3 FROM DUAL)
   WHERE t.lvl+1=s.price_id
         AND (cnt=4 AND left_4>0 OR cnt=3 AND left_3>0)
   )
SELECT result||'='||val
FROM t 
WHERE lvl=5 AND MOD(val,10)=0;


RESULT||'='||VAL
----------------------------------
1*3 2*4 3*3 5*4 10*3=70

By: newkid

newkid — Fri, 25 Jun 2010 19:18:06 +0000

WITH stamps AS (
SELECT ROWNUM n
      ,(CASE WHEN ROWNUM IN (1,2) THEN 4 ELSE 3 END) AS m 
      ,DECODE(ROWNUM,4,5,5,10,ROWNUM) val
  FROM DUAL 
 CONNECT BY ROWNUM<=5
)
,t1 AS (
SELECT id,n,TO_NUMBER(SUBSTR(t.m,stamps.n,1)) m
  FROM (SELECT ROWNUM id, m
          FROM (SELECT DISTINCT REPLACE(SYS_CONNECT_BY_PATH(m,','),',') m
                  FROM stamps
                 WHERE LEVEL=5
                CONNECT BY NOCYCLE n<>PRIOR n AND LEVEL<=5
                )
        ) t
      ,stamps
 )
SELECT * FROM (
SELECT t1.id,t1.m,s.val,SUM(t1.m*s.val) OVER(PARTITION BY t1.id) total
  FROM t1,stamps s
 WHERE t1.n = s.n
 )
WHERE MOD(total,10)=0
ORDER BY id,val;

        ID          M        VAL      TOTAL
---------- ---------- ---------- ----------
         3          3          1         70
         3          4          2         70
         3          3          3         70
         3          4          5         70
         3          3         10         70